Hi,
We have an issue where 3CX is not sending password reset (or welcome) emails to two specific extensions, despite the email addresses being valid and confirmed working.
Setup:
- Microsoft 365 / Exchange Online
- Two affected extensions use email addresses that are aliases (proxy addresses) of the SAME physical mailbox as a third, working extension's email address
What works:
- The extension using the primary/main alias address receives password reset and welcome emails from 3CX successfully
- Manually sending a test email (from our own mailbox) to either of the two other alias addresses arrives in the mailbox instantly and correctly
What doesn't work:
- Triggering "Forgot Password" / password reset from 3CX for the extensions using the other two alias addresses results in no email at all
What we've already ruled out:
- Confirmed via Exchange Message Trace: zero incoming attempts from 3CX to either affected address in the relevant time window (i.e. 3CX does not appear to even attempt sending to these two addresses)
- Confirmed the email field is correctly saved on both extensions with no typos
- Confirmed no mail flow rules in Exchange blocking these addresses
- Confirmed plus-addressing is not the cause (these are true Exchange proxy addresses, not +tagged addresses)
- Confirmed no duplicate use of these email addresses across other 3CX extensions
- Confirmed the mailbox itself has no delivery restrictions blocking external senders
Since mail is proven to reach the mailbox fine from other senders, and the only variable is 3CX sending specifically to these two alias addresses (while successfully sending to the third alias on the same mailbox), this points to something on 3CX's side failing to send to these two particular extensions/addresses specifically.
Has anyone seen this before, or know what might cause 3CX to silently fail on some aliases of a shared mailbox but not others?
Thanks!
We have an issue where 3CX is not sending password reset (or welcome) emails to two specific extensions, despite the email addresses being valid and confirmed working.
Setup:
- Microsoft 365 / Exchange Online
- Two affected extensions use email addresses that are aliases (proxy addresses) of the SAME physical mailbox as a third, working extension's email address
What works:
- The extension using the primary/main alias address receives password reset and welcome emails from 3CX successfully
- Manually sending a test email (from our own mailbox) to either of the two other alias addresses arrives in the mailbox instantly and correctly
What doesn't work:
- Triggering "Forgot Password" / password reset from 3CX for the extensions using the other two alias addresses results in no email at all
What we've already ruled out:
- Confirmed via Exchange Message Trace: zero incoming attempts from 3CX to either affected address in the relevant time window (i.e. 3CX does not appear to even attempt sending to these two addresses)
- Confirmed the email field is correctly saved on both extensions with no typos
- Confirmed no mail flow rules in Exchange blocking these addresses
- Confirmed plus-addressing is not the cause (these are true Exchange proxy addresses, not +tagged addresses)
- Confirmed no duplicate use of these email addresses across other 3CX extensions
- Confirmed the mailbox itself has no delivery restrictions blocking external senders
Since mail is proven to reach the mailbox fine from other senders, and the only variable is 3CX sending specifically to these two alias addresses (while successfully sending to the third alias on the same mailbox), this points to something on 3CX's side failing to send to these two particular extensions/addresses specifically.
Has anyone seen this before, or know what might cause 3CX to silently fail on some aliases of a shared mailbox but not others?
Thanks!
