Nick,
Same issue here, reported in another topic (Forgot password - Emails with reset link not received?). My email is also on Office 365 (Business), and I happen to be admin of the domain, and nothing in messages tracing either.
I did manage to get through to someone helpful on their billing support, their initial response was that my email server (i.e. Microsoft’s) was throttling their emails - but after a few exchanges they issued a manual reset link over email.
Something odd must be going on - I whitelisted the plex.tv domain (set spam confidence level to -1 to bypass checks), then also added a manual transport for the source IP sending these emails (I had tested the “forgot password” function on a test account I have with a gmail address, and that came in instantly - could tell which IP the email came from by looking at message headers). But nothing has come in. Out of the 7-8 attempts to reset password, I only got one email, some 7-8 hours later (and the token for that one had already expired). Nothing else has come in since then.
But emails from their support desk and marketing emails are fine (same domain), so I’m suspecting something with the sending SMTP server on their side (must be a different server sending reset emails). Not much we can do there, but posting here in case someone from Plex reads this and is nudged to have a closer look!
