SMTP server not working on one device

[NFtoBC]

So this morning I check my email, and get an error on sending that my Telus email or password is incorrect when replying from my iPhone. The credentials are unchanged from yesterday when it did, though I have travelled from BC to AB.
 
Using my iPad, tethered to the iPhone, with same credentials, sends without error. 
 
Any ideas why, or how to correct this?
 
Incoming mail works as expected, and uses same credentials!

[NFtoBC]

And now, with no changes to credentials on my phone, it works!?!?!?!!!

[NFtoBC]

Now running into the same problem while connected to AB parks Wi-fi. Can't sent via Telus server, but can through Gmail.