Rootcause: "Get Exchange Mail Messages: One or more errors occurred."

A process implementing “Get Exchange Mail Messages” stops working out of the blue with the error message “One or more errors occurred.”.
Researching the issue brought a handful of posts in the forum re/ the dreaded

Get Exchange Mail Messages: One or more errors occurred.

UiPath.Mail.Activites = 1.12.3
UiPath Studio 2020.10.8
UiPath Robot 20.10.8

Analyzing the inbox in question showed:

  • there were 2 or more emails
  • from the same sender
  • at the same hour:minute
  • with the same subject
  • and even the same content

Removing manually all but 1 email made the activity “Get Exchange Mail Messages” working again.

Maybe only a subset of From, datetime, subject already triggers the bug (I believe it is one!) but I cannot produce these testcases.

Implement a batchsize for the Options: Top with a backoff algorithm.
Because even if such “blocking” mails exist the activity will work fine with Top 1

WIth “backoff algorithm” I mean if typically batches of 30 mails are read and processed/queued, then that value should decrease down to 1.
If successful, increase up to the origial value (e.g. 30)

Following up on this older thread:

This problem of mine was finally solved in mail server infrstructure. In RPA I could only add defensive code with retry-scopes.

Advise: If you have this problem sporadically insist, insist, insist on backlevel-grade mail support. Make minimal example code so that you can supply fresh timestamps to logfile-level anaylsis by mailserver support.

It’s more likely that it’s a security feature in Exchange to stop spam etc.

Can you tell us what email support changed to fix it?

When the fix came in, I went on to close my tickets, did not interview them deeper. So can’t elaborate on that, sorry.