Hi Johnny,
it's a tricky issue to debug, specially because it only happens sometimes.
it's a tricky issue to debug, specially because it only happens sometimes.
You can try to apply this patch to your Moodle site and see if it fixes the problem. If the problem is caused by airnotifier, this patch should fix it. If it's caused by something else (e.g. the SMTP server) then it can still happen.
Cheers,
Dani