Solved! It looks like my mobile data provider (Vodafone) is interfering with traffic to port 143 to hide STARTTLS. I'll probably never find out the official reason but I suspect a weak attempt to allow them to intercept viruses.
By modifying router to allow IMAP to use a different port I've got it working again. On Monday, 10 December 2018 08:46:58 UTC, Andrue Cope wrote: > > Hi, > > Every now and again K9 complains that it can't start a secure connection > to my server (it's a server I run at home) because there's a certificate > error. It *seems* to be related to moving from wifi to WAN. I have > checked my certificate both on desktop machines at work and using Chrome on > the mobile and they report no problems with my certificate. Restarting the > phone sometimes cures it but not this time. > > The error message is 'Cannot connect to server. (STARTTLS connection > security not available).' > > Looking at my server logs the only thing I can see is multiple IMAP > connections that abort. > > There's no actual evidence that K9 has even tried to connect. > -- You received this message because you are subscribed to the Google Groups "K-9 Mail" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. For more options, visit https://groups.google.com/d/optout.
