MicrosoftMicrosoftWe've begun receiving 5.7.515 errors showing "Dkim= Fail". Every tester I've run our email through shows DKIM passing completely. All domains in the header match the sending domain. Any help?
For about a week now, we've also observed a slight occurrence of dsn=5.7.515 errors. Upon checking the logs, we found that 0.01% of all email sends resulted in "Dkim= Fail", while the remaining 99.9% were successfully delivered. The original messages in the actual bounce emails clearly had correct DKIM signatures, and all sender domains are the same, so we haven't been able to identify the cause of the DKIM=Fail errors. We'd appreciate any potential solutions.
This occurs because Microsoft uses very short DNS timeouts, if the DKIM controller doesn't receive the DNS reply quickly enought, then they will judge that DKIM fail.
Setting long TTL (at least 48h) on your DKIM records will help mitigate the problem.
I don't see how the TTL would affect that -- that just tells the DNS system how long to cache results. Nothing to do with how long it takes MS to fetch the records. . .
Please correct me if I'm wrong.
same here
Please let me know if you get a resolution. I'll post here, as well, if I find something.
