Mail only enqueued

[Jose Antonio Espinosa Villanueva]

Today our server poste.io 2.0.20 free is only queuing the inbound mail and not delivering to the email accounts. Yesterday everything was ok, what can cause this?

[Jose Antonio Espinosa Villanueva]

Updated to the last version and delivered for a while, after increase memory (this version seems to consume more of it) the problem arises again. The fact is now it is only possible to send emails but users are not receiving emails because they are accepted, enqueued and not delivered to the user. What can I do?

[Scott MacDonald]

What are the specs for the VM on which you are running the poste.io container?

[Jose Antonio Espinosa Villanueva]

Previously an Azure B2s standard (2vcpu, 4Gb memory). I have to update to B2m (2 vcpu, 8Gb memory)

[SB]

B-series is burstable, Azure cripples the resources if it exceeds them for a certain period of time. Try D1/D2 for full hardware usage. (D1 are only approx. £20/month as reserved instance for 3.5 GB dedicated RAM).

Your B2s capacity should not exceed 40% of available resources for a prolonged period. https://azure.microsoft.com/en-us/blog/introducing-b-series-our-new-burstable-vm-size/

Also, did you ask Microsoft to unblock email on your subscription (if it's made after Nov-2017)? By default they stop it working unless you ask them specifically to enable.

[SB]

Found it - https://blogs.msdn.microsoft.com/mast/2017/11/15/enhanced-azure-security-for-sending-emails-november-2017-update/

[Jose Antonio Espinosa Villanueva]

No, I think this is not the case because we had not any trouble in sending emails (we have sent some thousands until now), I think we have an older subscription to Azure.

Also we don't need so much memory/cpu for normal operation, just in case some smtp attacks we receive from time to time as you can see bellow.

[SB]

I am not surprised there is a delay with so many incoming! That's crazy, and I thought we got a lot... you are getting 100k emails in the last 2 day, I bet it is still trying to process them! Also you blacklist must be HUGE and take a long time to check against. Could you change your IP address? Is Azure Firewall on? What is the threshold for bad command to blacklist them?

[SH]

It seems that it is caused by pooling which was enabled that time. At 2.1.1 was haraka pooling disabled (caused multiple delivery problems at some corner cases). I believe that this is fixed at current Haraka version (https://github.com/haraka/Haraka/issues/2602) but we have not tested and I will not enable pooling until it will be proven to work.

So last version should deliver little slower (connection per email) but battle tested. Ofcourse if it is issue for you even with new version, please reopen