What are the most common email deliverability issues you faced?

We know the most common ones, but would like to know from the actual users what they faced.

 

most likely, sending emails to outdated and invalid email addresses.

 

Sometimes my sending IPs are blocked by public backlists, like Spamhaus ZEN and UCEPROTECTL2/L3. My hosting instances sometimes got vulnerable PHP scripts from clients then I always need to scan and secure them. Spamhaus allows unblocked by yourself but UCEPROTECTL2/L3 doesn't.

 

machine open emails.

Machine-opened emails are used by people who do not want to read an email but must subscribe to receive the benefits. So a robot opens the email, and while some Webmail platforms may not make distinctions, most do. This means that your mail is considered a bounce or fake delivery. The numbers are astronomical at times and it can be costly to eliminate them.

 

Having proper SPF and DKIM records is crucial for a normal e-mail deliverability. Issues with those simple records may even force your IP to be blacklisted. Carefully look for the proper email server configuration your hosting providers brings you.

 

Blocking by IP address is probably the most annoying thing that can happen...
If the sender's IP address is blacklisted, emails may be rejected or marked as spam.

 

Emails go to spam folders even after following best practices for authentication and list hygiene.
Low open rates due to emails being blocked or not making it to the inbox.
Dealing with a high bounce rate resulting from outdated or inaccurate email lists.

 

Users experience email deliverability issues like:

• High bounce rates (invalid or undeliverable addresses).
• Spam traps and blacklists catching legitimate emails.
• Missing email authentication (SPF, DKIM).
• Unengaged subscribers leading to spam filtering.
• Emails flagged as spam due to suspicious content or design.