Hi Jean,
Thanks for posting the question on our form.
According to your description, I want to confirm if you have turn on external sharing.
If not, please turn on it via the following article:
Turn external sharing on or off
If you have turned on it and the issue still exists, I suggest you turn on it via PowerShell:
- Download, install and open SPO Management Shell
https://www.microsoft.com/en-us/download/details.aspx?id=35588
- Login
$adminUPN="******@company.com"
$orgName="company"
$userCredential = Get-Credential -UserName $adminUPN -Message "Type the password."
Connect-SPOService -Url https://$orgName-admin.sharepoint.com -Credential $userCredential
- Turn on external user sharing
Set-SPOSite -Identity https://company.sharepoint.com/sites/group-share -SharingCapability ExternalUserAndGuestSharing
Here is a thread who meet the similar issue, they solved it via the suggestion:
Unable to Share with External Users
If you still can’t share it with external user, could you please provide the following information for further analysis?
- Check if all files meet the issue.
- Confirm if all sites meet the issue.
- The screenshot of error message.
Regards,
Qing