If it helps these are the steps that I followed to get Outlook to sync with my btinternet.com account
Settings -> Add Account
Add an email account
Enter full email Address
Not Yahoo? (top right hand corner)
Change Account Provider
Tap tick mark (top right Corner)
Outlook should now sync with your email account
That's exactly what I have been doing. Don't know why it's gone pear shaped after working well for months it's just so frustrating.
It gets worse!
Notwithstanding an update to the "Outlook" app I still can't connect to my BTMail on android phone. My android tablet which had been working perfectly with Outlook appears to be unable to download any BT Mail emails since last Wednesday.
Another android email client and Outlook 365 on PC are behaving as they should.
I wanted to use the Outlook app as I erroneously thought that it would integrate better with Outlook 365 on my PC but perhaps I should just better stick with "BlueMail".
That should leave you with a fresh install of Outlook with no settings, enter them again and see if that works.
Last desperate measure would be to uninstall and re-install the app - got to be worth a try if all else fails
Thank you again
Well it has nearly worked - managed to set up accounts but will only download emails up until 14 February - seems strange.
I have uninstalled and reinstalled the app several time to no avail.
I'll hang fire and see if anything else transpires
Having just checked my phone I see that it hasn't synced with my BT account since 12/Feb although I know I have more recent emails than that. I'm guessing that Outlook either assumes the wrong port numbers or is trying to use STARTTLS which bt don't support, impossible to tell because the Andoid app doesn't seem to allow access to these settings