Over the last month or so we have been unable to retrieving email over IMAP (port 993) when connected to the broadband using wired or wireless. In short the solution was to reboot the BT router. I only did this in the last hour so I will have to wait and see if the issue returns.
I have seen various other posts potentially about the same issue so the following is a slightly longer description if it helps anybody else.
On the various iPhones in the house they collect mail whilst on cellular data but fail when on WiFi.
I have an enterprise class firewall just inside the router which captures logs so I could see that port 993 was being passed to the BT router. It also allows the testing of ports directly against the router, which showed port 993 was not connecting out. I also did a DNS lookup to ensure the domain was resolving to the correct IP (this is not BT supplied email).
Having looked at everything else I finally looked at the BT router. As far as I can tell the router does not collect any traffic logs to see what is going on so I ended up rebooting the router.
When it came back online the port test from the firewall works and devices can again collect email whilst on the network which suggests it was the router to blame. I now wait to see if the issue returns.
