I have a similar issue using the Bt email app on my iPhone on home wifi. I keep getting authentication buffering. Works without any issue on other networks. Home router is Netgear orbi
I would appreciate the solution being provided here please. I can access my email on Android phone but not on android tablet. Exactly the same error message
Remove the BTMail app which is not a very good app and install the free Bluemail app which is far better.
This is happening to me too. Just happened suddenly. I also have a Samsung tablet. Did you get it fixed?