are there any news on this issue? We still have issues when closing multiple tickets in batch or a lot of tickets one by one. Randomly our zammad installation tells us in Channel-settings that it “Can’t use Channel::Driver::Smtp: #<EOFError: end of file reached>”.
We have found a workaround/configuration option for our use case.
With the following command you can see the configured “MessageRateLimit” on your onPrem Exchange-servers: Get-ReceiveConnector | ft name,MessageRateLimit
For us it worked out to higher the configured limits on each server.