One of the biggest problems for people using business email is sending messages that end up in spam or do not arrive at all. You may have a professional email such as info@company.co.tz, sales@company.com or support@business.co.tz, but when you send messages to customers, some may not see them in the inbox. Others may find them in spam, promotions or junk folders.
This is a serious problem for businesses, institutions, schools, churches, companies and anyone using email for work. If an email goes to spam, a customer may not reply, an invoice may be missed, a quotation may be ignored, an application may fail to arrive, or important information may be delayed.
The first reason emails go to spam is missing or incorrect domain authentication. Domain authentication is a way of proving that emails sent from your domain are legitimate. This is where SPF, DKIM and DMARC are used.
SPF stands for Sender Policy Framework. It is a DNS record that states which servers are allowed to send email on behalf of your domain. For example, if your domain is example.co.tz and you use a hosting server to send email, your SPF record should show that the server is allowed to send emails for that domain.
If SPF is missing or incorrect, the receiving server may fail to verify your email. As a result, the email may go to spam or be rejected completely. This is common when people use domain emails without setting correct DNS records.
DKIM stands for DomainKeys Identified Mail. DKIM adds a digital signature to your email. This signature helps the receiving server confirm that the email came from a legitimate source and was not changed during delivery. DKIM is very important because it increases trust in your emails.
If DKIM is not enabled, your emails may appear weak in authentication. Even when SPF is correct, DKIM improves the chance of reaching the inbox instead of spam.
DMARC stands for Domain-based Message Authentication, Reporting and Conformance. DMARC uses SPF and DKIM to decide what should happen when an email fails authentication. DMARC can allow the email, quarantine it or reject it. It can also send reports to the domain owner showing who is sending email using the domain.
For any business using domain email, SPF, DKIM and DMARC are very important. Without them, someone else may try to send email pretending to be from your domain, and your legitimate emails may also look untrusted.
The second reason is incorrect SMTP settings. SMTP is the system used to send email. If you use a website, system, printer scanner, CRM or app to send email, SMTP must be configured correctly. SMTP settings usually include server, port, username, password and encryption.
Example settings may look like this:
SMTP Server: mail.example.co.tz
Port: 465 for SSL or 587 for TLS
Username: info@example.co.tz
Password: email password
Encryption: SSL or TLS
If you use SMTP that does not match your email domain, the message may look suspicious. For example, sending email from info@example.co.tz through a server that is not allowed in SPF may cause spam problems. This is why your SPF record must include all servers that send email for your domain.
The third reason is sending too many emails suddenly from a new domain. If your domain or email address is new and you immediately send many emails in one day, email providers may treat that behavior as spam. Email reputation is built slowly.
For a new domain, start with low sending volume. Send important emails to people who know you, make sure they reply, and avoid bulk messages without proper setup. As your domain is used properly and people engage with your emails, reputation can improve.
The fourth reason is email content that looks like spam. Certain words and writing styles may increase the chance of spam filtering. Examples include too many promotional words such as “free money,” “win now,” “urgent offer,” “click here,” or using too many capital letters and exclamation marks.
A good business email should be normal, clear, respectful and not overly promotional. Avoid misleading subject lines. The subject should match the email content.
The fifth reason is large or risky attachments. Emails with very large attachments may be delayed, rejected or sent to spam. Attachments such as .exe, .bat, .js or suspicious .zip files may be treated as dangerous. If you are sending a document, use PDF or another accepted format.
If the file is large, use a Google Drive, OneDrive or official system link, but make sure permissions are correct. Avoid strange or unclear shortened links because they may increase spam risk.
The sixth reason is too many links in one email. Emails with many links, especially from different domains, may look like spam. If you include links, keep them few and use trusted domains. For business email, it is better to link to your official website than to unknown links.
The seventh reason is not having a professional email signature. A signature does not guarantee inbox delivery, but it builds trust with recipients. A business email should include a name, position, company, phone number, website and contact details. This helps the recipient know that the email comes from a real person or organization.
The eighth reason is sending to a poor-quality email list. If you send emails to people who did not give permission, many may mark your message as spam. This damages your domain reputation. Also, if the list contains many invalid addresses, your bounce rate increases and reputation drops.
For email marketing, use a legitimate list of people who subscribed or are connected to your service. Include an unsubscribe option for newsletters. Do not buy email lists without knowing their source.
The ninth reason is using shared hosting with poor email reputation. If you use shared hosting, your emails may be sent from a server used by many other people. If other users on that server send spam, the shared IP reputation may affect your emails too.
For important business email, consider using an email provider with good reputation or a transactional email service if your system sends many notifications, receipts, OTPs or invoices. This reduces shared IP reputation problems.
The tenth reason is missing or incorrect reverse DNS or PTR records. This is more advanced and is usually handled by the server provider. Receiving servers may check whether the sending IP has reverse DNS that matches the mail server. If it is missing or incorrect, the email may look suspicious.
If you use normal hosting, your provider should manage this. If you use your own VPS and send email directly, you must understand DNS, PTR, mail server configuration and security. Sending email directly from a VPS without proper configuration often leads to spam problems.
The eleventh reason is using a different from-address from the SMTP account. For example, the SMTP account may be admin@example.com, but the system sends as billing@example.com without proper permission. Some servers allow this, others reject it, and receiving servers may see a mismatch. It is better to use a from-address that matches the SMTP account or configure aliases and permissions correctly.
The twelfth reason is poor HTML email code. If your email has broken HTML, images from untrusted sources, scripts or messy layout, it may affect deliverability. Email templates should be simple, responsive and free from dangerous code. Do not use JavaScript inside email.
The thirteenth reason is missing a plain text version. Professional emails are often sent with both HTML and plain text versions. Plain text helps the email look more natural and improves compatibility. If you use an email marketing or transactional email service, make sure a plain text version exists.
The fourteenth reason is low engagement. Email providers may consider whether recipients open, delete, reply to or mark your emails as spam. If many people ignore or report your emails, your reputation can decline. Your content should be useful to recipients.
The fifteenth reason is a domain with bad history. If your domain was previously used for spam or owned by someone else, it may already have poor reputation. Before buying an old domain, it is wise to check whether it has been blacklisted or misused.
To fix emails going to spam, start with SPF. Open your domain DNS management and make sure an SPF record exists. SPF is usually a TXT record. A simple example may look like:
v=spf1 include:_spf.google.com ~all
This example is for Google Workspace. If you use another provider, the record will be different. Do not copy SPF records without knowing what your provider requires. Get the correct SPF record from your email or hosting provider.
Remember that a domain should usually have only one SPF record. If you have two separate SPF records, that may cause an error. Instead of having two records, combine them into one.
After SPF, enable DKIM. For Google Workspace, DKIM is generated in the admin console and then added as a TXT record in DNS. For other hosting providers, you may find DKIM records in cPanel or your email control panel. After adding the DNS record, return to the email provider and verify or activate it.
After DKIM, set up DMARC. At first, use a monitoring policy so you do not accidentally block legitimate email. A starting DMARC record may look like:
v=DMARC1; p=none; rua=mailto:dmarc@example.co.tz
The p=none policy does not block email. It collects information. After confirming that SPF and DKIM are correct, you can move the policy to quarantine or reject depending on your security needs.
If you are not experienced with DMARC, do not start directly with p=reject before testing. You may block legitimate email if SPF or DKIM is not configured correctly. Start slowly, review reports and improve.
For SMTP, make sure your system uses authentication. Do not use a mail server without username and password. Use the correct port, encryption and from-address. If your system is Django, WordPress, Laravel or a custom app, make sure email backend settings are correct.
For websites or systems that send many emails such as OTPs, receipts or notifications, it is better to separate transactional email from normal email. Transactional emails are automatic messages from a system. They need strong deliverability because they may be important for login, payments or verification.
Also make sure marketing emails include an unsubscribe option. Transactional emails such as password reset or receipts do not require unsubscribe in the same way, but newsletters and promotional emails should allow users to opt out.
Another important step is testing your emails. Send test emails to Gmail, Yahoo, Outlook and other domain emails, then check whether they go to inbox or spam. Check email headers to see whether SPF, DKIM and DMARC pass or fail. Email headers provide very useful troubleshooting information.
If an email shows SPF: pass, DKIM: pass, and DMARC: pass, it has a better chance of reaching the inbox. If one fails, check DNS records, SMTP server or from-address.
Avoid sending many emails using BCC to a large list. This may look like spam. If you are sending a newsletter or announcement to many people, use an email marketing tool that handles unsubscribe, bounces and list management properly.
For business email, use clear subject lines. A good example is “Quotation for Website Development Service” or “Invoice for June Hosting Renewal.” A bad example is “OPEN NOW!!! VERY IMPORTANT FREE OFFER!!!” The second type may increase the chance of going to spam.
For attachments, reduce PDF size before sending. Use professional file names such as Invoice-2026-001.pdf instead of scan0001.pdf. Attachments with strange names may look suspicious to recipients.
If your emails are already going to spam, do not increase sending pressure. First fix authentication, reduce sending volume, send email to people who know you, ask them to reply, and avoid bulk campaigns for a while. Reputation needs time to recover.
In general, emails going to spam are rarely caused by one issue only. The problem may involve DNS records, SMTP settings, domain reputation, IP reputation, email content, attachments, links, list quality and sending behavior. That is why the solution requires checking the whole system.
Remember: business email is not only about having a nice address. It must have proper DNS authentication, a good sending server, clean content, account security and respectful sending practices. When SPF, DKIM, DMARC and SMTP are configured properly, your emails have a much better chance of reaching the inbox instead of spam.