Hello Everyone,
We are currently encountering an issue where the maximum number of concurrent connections to the Exchange server (MailBox2019-2) has been exceeded, resulting in the closure of the transmission channel
The maximum number of concurrent server connections has exceeded a per-source limit, closing transmission channel (MailBox
Thank you!
Were you sending lots of emails when that happened? How many parallel celery processes are there? By default it uses one per CPU core, but you can pass e.g. -c 4 to the indico celery worker command to limit it ti 4 parallel processes.
FWIW, you could also ask your mail admins to allow a higher amount of concurrent connections from your server.
Thanks for your reply.
Yes, I sent around 1,000 emails from the Indico system. We encountered this issue only after enabling threading with 2 threads and 32 workers.
Our mail team informed me that we can have 20 concurrent connections, and it’s not recommended to allow more.
Threading should not matter here since emails are by default sent via Celery tasks.