Common Problems

Common Errors

Error code: 550 sorry, you can't send as this user

Symptom: The messages that you send out come back as a bounce message with the following error:

Cause: You are not allowed to send emails on behalf of this user. We have enabled a strict check to see if the sender matches the authenticated user, or is related to it somehow.

Solution: Authenticate as the same user you wish to send or log in to your Admin Panel to define other email addresses that can send as this user (Admin Panel → Users → click on Permissions for the desired user → Send email as).

 

Error code: 550  sorry, no mailbox here by that name

Symptom: The messages that you send out come back as a bounce message with the following error:

Cause: The system is attempting to deliver the email locally, but the specific user account does not exist on our servers. This often occurs during the testing phase of a migration if certain mailboxes have not been created yet.

Solution: If you are still in the process of migrating and have not created all accounts, you can temporarily disable local delivery for the domain. This forces the system to look externally for the mailbox.

1. Log in to the Admin Panel.

2. Navigate to Domains and click Edit on the affected domain.

3. Locate the Local Delivery setting and change it to "No".

4. Important: Once your migration is complete and all mailboxes are created, remember to switch Local Delivery back to "Yes" to ensure internal mail routing works correctly.

Error code: 550 sorry, you are blacklisted on this server 

Symptom: The sender receives a bounce message with the following error:

Cause: You have blacklisted this sender on our servers.

Solution: Remove the blacklist from your Admin Panel (Admin Panel → Filtering → Blacklist → check Include Users Blacklist → search for the sender's email or domain → remove the entries). Alternatively, you can access your email's User Panel and go to Filtering →  Blacklist → do a Control F and search for the sender's email address, then click on the minus sign next to it, to remove it.

Error code: That sender cannot send mail here 

Symptom: The message is not delivered and in the Incoming Logs the delivery status is Rejected and you see this message:

Cause: The sender's domain is blacklisted. Usually, it's a TLD that has a very bad reputation.

Solution: Open a support ticket requesting the whitelisting of the domain.

Error code: You have exceeded your messaging limits

Symptom: When sending out a message, you receive the following error:

Cause: You have sent more than 300 emails (for Basic) or 1200 emails (for Enhanced) during the day thus reaching your daily send limit.

Verification: If you hit this limit, you can use the Track Deliveries option in the User Control Panel to see your activity for the last 24 hours.

Solution: If you did not send that many emails, immediately run a full virus scan of your computer, change your email address password or contact your administrator.

Error code: 553 sorry, that domain isn't in my list of allowed rcpthosts

Symptom: The messages that you send out come back as a bounce message with the following error:

Cause: SMTP Authentication is not enabled in your e-mail client

Solution: Enable SMTP Authentication in your e-mail client

Error code: 4.4.2

Symptom: The email client is getting the following error:

Cause: Your email client hasn't sent a command in 20 seconds

Solution: Verify your email client and internet connection

Fixing Constant Username & Password Requests

Symptom: When sending messages out, the server repeatedly asks for your username & password, despite having entered the right ones

Cause: If you are sending out using the regular port 25, it is possible that your local Internet Provider is intercepting SMTP communications on port 25 and forcing you to use their own SMTP servers. Your SMTP credentials would thus fail against their servers

Solution: Change your outgoing SMTP server port to another value. You can use ports 26 or 587 for regular/TLS server or port 465 for SSL service.

Sender receives: sorry, you are blacklisted on this server

Symptom: When someone sends you an email, they get the error below:

Cause: You changed default domain or user filtering settings inside the Filtering option. Instead of using the default Accept e-mails from Everyone, such option was changed to Accept e-mails from whitelist and address book only, which means account will receive e-mails only from addresses in the whitelist or contacts and all other e-mails will be rejected.

Solution: Change the mentioned option to Accept e-mails from Everyone. Verify both on admin (domain level) and user control panels, by clicking on Filtering, in the top menu.