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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.
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Symptom: When sending out a message, you receive the following error:Sorry, you are blacklisted on this server
Cause: Usually happens when you have your own account in its own blacklist and try to send a message to from/to yourself or when Outlook does its account test, during account setup.
Solution: Access your account's control panel, Filtering > Blacklist, do a Control F and search for your own e-mail address, then click on the minus sign (-) next to it, to remove it.
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Symptom: When someone sends you an email, they get the error below:
552 cuda_nsu sorry, you are blacklisted on this server
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 domain and user control panels, by clicking on Filtering, in the top menu.