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- Dec 23, 2022
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.. I constantly test various data centres and service providers to widen the range of our services.
We have just concluded a test purchase of a VPS at Contabo. The idea was to test PostalServer (opensource SMTP server solution) for 1 of our clients.
Postal Server is a fully featured open source mail delivery platform used mostly for setting up smtp servers, that a client can send out large amount of transactional/system emails. The system has been lately heavily used also by spammers to send out uncontrollable amounts of spam emails.
The onboarding process at Contabo was very smooth, I did set up Postal Server with some trial and error (from my side), and then we started testing the system emails:
1) the test email sent to mail-tester.com was perfect: 10/10
2) then we tried sending out system emails on successful registration (by creating test users), and noticed that these don't get delivered:
3) went to test the logs, and the system says "550 non-local sender verification failed":
The error "550 non-local sender verification failed" usually means that the recipient's server doesn't trust the domain name or IP a person is using >> if this happens, then most probably the email IP is blacklisted, and the messages will bounce.
4) Went and checked the blocklist just to find that this is exactly the case:
5) Opened a support ticket with Contabo.
Note: the support works really fast there - huge respect!
and here is the answer:
and also something with what our initial tests totally disagree:
.. time lost
.. the client needs his smtp server to work to be able to open the project. without this the project can't be started :/
.. I am not talking about a small WP website > this projects starts as a 5 server setup + an smtp vps.
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Verdict > Contabo should be avoided if your websites/systems there will be sending out emails.
Suggestion to Contabo >> Issues like these HAVE to be disclosed and easy to be seen.
We have just concluded a test purchase of a VPS at Contabo. The idea was to test PostalServer (opensource SMTP server solution) for 1 of our clients.
Postal Server is a fully featured open source mail delivery platform used mostly for setting up smtp servers, that a client can send out large amount of transactional/system emails. The system has been lately heavily used also by spammers to send out uncontrollable amounts of spam emails.
The onboarding process at Contabo was very smooth, I did set up Postal Server with some trial and error (from my side), and then we started testing the system emails:
1) the test email sent to mail-tester.com was perfect: 10/10
2) then we tried sending out system emails on successful registration (by creating test users), and noticed that these don't get delivered:
3) went to test the logs, and the system says "550 non-local sender verification failed":
The error "550 non-local sender verification failed" usually means that the recipient's server doesn't trust the domain name or IP a person is using >> if this happens, then most probably the email IP is blacklisted, and the messages will bounce.
4) Went and checked the blocklist just to find that this is exactly the case:
5) Opened a support ticket with Contabo.
Note: the support works really fast there - huge respect!
and here is the answer:
and also something with what our initial tests totally disagree:
.. time lost
.. the client needs his smtp server to work to be able to open the project. without this the project can't be started :/.. I am not talking about a small WP website > this projects starts as a 5 server setup + an smtp vps.
========
Verdict > Contabo should be avoided if your websites/systems there will be sending out emails.
Suggestion to Contabo >> Issues like these HAVE to be disclosed and easy to be seen.
