I have multiple users that range from iPhone 5 through iPhone 8 that since upgrading to IOS 11.x have had intermittent problems and the fix has been to remove the account and put the account back on the device.
For some users this problem occurred once.
I also have 4 or 5 users that the problem happens multiple times per week.
There seems to be no rhyme or reason to the phone or ios level except that they are at least on IOS 11.
I am hoping someone can point me to some exchange logs and tell me what to look for to resolve this issue.
It also seems that my exchange inetpub logs now are very large. Maybe something in those logs will help with this resolution
We know there have been multiple problems with IOS 11.
Any info is appreciated. et me know what additional information is needed