Hi there
Our SharePoint Online Admin > Policies > Sharing > is set to "Existing Guests".
How to add more/additional external users, so a specific site can be shared with them?
Thank you.
Hi there
Our SharePoint Online Admin > Policies > Sharing > is set to "Existing Guests".
How to add more/additional external users, so a specific site can be shared with them?
Thank you.
After enable external sharing at the organization level, make sure you also allow it at site level:

Then you could share site with people outside the organization directly:

More information for your reference:
https://docs.microsoft.com/en-us/sharepoint/external-sharing-overview
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From your decsription, it looks like you select the "Existing guests only" in site external sharing:
For this situation, we can go to Microsoft 365 admin center>choose Guest users under Users tab>Add a guest user>redirct to the Azure AD New user page to invite a guest user:


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