Hide from my organization's global address list in Microsoft O365

[Kadir_Ansari]

When we creating Group in Microsoft Teams from scratch Mail App is missing but when we creating from O365 group Mail App is there. Why..?

Please refer below screenshot.

NormalGroup : This group is created from scratch and mail app is missing.

Created from scratch

M365Group : This group is created from Microsoft 365 Group and mail app is exist by default.

[#2]

Because Microsoft introduced a change a while back, "hiding" Team-ified groups from Exchange clients. You can "show" them via PowerShell:

Set-UnifiedGroup -Identity blabla -HiddenFromExchangeClientsEnabled:$false