Issues with free.fr mails - Update 2
We got reports that users with mail accounts hosted by free.fr are missing mails sent by T³. We investigated the issue and found out that the T³ mail server got blacklisted by free.fr for causing too many "errors". Thereby they don't mean spam, but more technical issues like trying to reach invalid mail recipients. According to our logs this started 4 weeks ago. Due to the fact how mail delivery works the mails aren't lost. They are pending in the mail queue and our server retries the delivery, but free.fr blocks our server every 24 hours again. It maybe that the retries cause the re-blocking, so we maybe have to trash the pending mails.
We dug deep into the logs, but couldn't find any real technical reason for this to happen yet. The mail server has a good reputation in general and is not listed on any major spam blacklist.
We'll continue to solve this issue and can only ask to ensure you're using a valid mail address on T³ and maybe use another mail provider instead of free.fr.
After furthing log evaluations we can say that the problem exists for 4 weeks. We also found an issue with our newsletter system being open to some abuse, but we fixed this. We also dropped the mail queue to be sure that no "bad" mails are pending. Unfortunately we still cannot deliver mails to free.fr as they are still blocking (all valid) requests from our mail server. We contacted their support asking for assistance. There's noting more we can do at the moment. Please change your mail address, if you depend on receiving our mails. We're sorry for this inconvenience.
It seems that free.fr finally unblocked us some days ago.