Hi, @Roger Roger
According to your description, you want to remove the policy globally.
You are trying Grant-CsApplicationAccessPolicy, but an error occurs due to the parameter '$Null'. In fact, the “Grant-CsApplicationAccessPolicy” cmdlet does not accept the '$Null' parameter.
To globally remove a policy, the correct syntax should not include $null. Instead, you should use the Remove-CsApplicationAccessPolicy cmdlet to remove the policy.
Remove-CsApplicationAccessPolicy -PolicyName “TempPolicy1” -Global
More information can be found Remove-CsApplicationAccessPolicy (MicrosoftTeamsPowerShell) | Microsoft Learn
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