Internal Server Error connecting to O365 Exchange using OAuth

Graham Jenkins 6 Reputation points


We have an app registered in Azure which allows our software to "import" emails from mailboxes into our software using OAuth; as well as send outbound emails via our software. Since yesterday, we have noticed that emails are getting duplicated in our system as well as connectivity errors for outbound emails.

We have tried various logging but the only error that is getting returned is "An internal server error occurred. The operation failed" (See Trace below) This is affecting multiple users across multiple sites connecting to their own O365 Exchange. Only affecting OAuth connections, Basic Authentication works fine. No updates to our software have been made.

Any ideas?

<Trace Tag="EwsResponse" Tid="24" Time="2022-08-24 14:19:16Z" Version="15.00.0913.015">
<?xml version="1.0" encoding="utf-8"?>
<s:Envelope xmlns:s="">
<Action s:mustUnderstand="1" xmlns="">*</Action>
<faultcode xmlns:a="">a:ErrorInternalServerError</faultcode>
<faultstring xml:lang="en-US">An internal server error occurred. The operation failed.</faultstring>
<e:ResponseCode xmlns:e="">ErrorInternalServerError</e:ResponseCode>
<e:Message xmlns:e="">An internal server error occurred. The operation failed.</e:Message>

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