Update: This issue is fixed in Outlook Desktop Version 2402 Build 17328.20068 and higher

Ran into an issue with an update to M365 Apps where ActiveSync FolderSync breaks with connection resets on Outlook version 16.0.17126.20182.

To find out the build version in Outlook, go to File > Account

To find out the build version from a command line:

reg query HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Office\ClickToRun\Configuration /v ClientVersionToReport

Microsoft is investigating and has issued the following workaround: https://support.microsoft.com/en-us/office/outlook-desktop-exchange-activesync-connections-stopped-working-in-version-2401-da2dc0dd-297e-48ba-b6d9-ab18f5d522fc

The command to downgrade the M365 Apps:

cd %programfiles%\Common Files\Microsoft Shared\ClickToRun
officec2rclient.exe /update user updatetoversion=16.0.17126.20132
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