Hi Elroy,
Welcome to our forum.
After you reverted back to 2.0, we suggest you recycle MsOWAAppPool or reset IIS to check if the issue persist:
Recycle app pool:
https://technet.microsoft.com/en-us/library/cc770764(v=ws.10).aspx
Reset IIS:
IISReset /NoForce
Best Regard,
Jim Xu
Please remember to mark the replies as answers if they help, and unmark the answers if they provide no help. If you have feedback for TechNet Support, contact tnmff@microsoft.com.
Jim Xu
TechNet Community Support
