Hi Mohamed Al-Qady,
Thank you for posting on Microsoft Forum.
Based on your description, you said that you get an error "We can't update the policy right now. Try again" whenever you try to enable "External participants can give or request control" in the portal.
You need to be the Office 365 Administrator, if not, contact your IT department, Login to https://admin.teams.microsoft.com Navigate to “Meetings > Meeting policies > Global (Org-wide default)” (Or desired policy) Scroll down to “Content sharing” section then enable “Allow an external participant to give or request control”
To use PowerShell to control whether external participants can give control or accept requests for control, Connect to Teams Connect-MicrosoftTeams (MicrosoftTeamsPowerShell) | Microsoft Docs then run the command Set-CsTeamsMeetingPolicy -Identity SalesMeetingPolicy -AllowExternalParticipantGiveRequestControl $True. For more regarding the Teams meeting policy, refer to **** Set-CsTeamsMeetingPolicy (SkypeForBusiness) | Microsoft Docs, Share content in a meeting in Teams (microsoft.com)
Looking forward to hearing from you.
Best Regards,
De Paul