[sync] ActiveSync not working on iOS 11.2.6

[Alex]

Dear all,

ActiveSync is no longer working on since upgrading to iOS 11.2.6. Microsoft
ActiveSync tester gives no error message on Activesync. The sync also works
with Android without problems.

I have deleted the ActiveSync account on the iPhone and set-it up again. I
get the following error message when setting up the account: "unable to
verify account information".

Any idea what I can do to debug/solve? Please help.

Thank you,
Alexander