We have recently converted to using OAuth with Exchange Online from Basic Authentication.
Just starting today, a number of customer sites reported the following errors, sometime intermittently:
Rebex.Net.EwsException: Internal server error. An internal server error occurred. The operation failed. ---> Rebex.Net.EwsException: Internal server error. An internal server error occurred. The operation failed. ---> Rebex.Net.EwsException: Internal server error. An internal server error occurred. The operation failed.
In some cases this is intermittent and in other cases it is regularly reproducible. The strange thing is that this has been working properly for the last week or two since our customer started using OAuth.
Any assistance would be much appreciated.