SharePoint: Sorry you don’t have access —to share file(s) with: people with existing access
Guest users can be invited to your SharePoint tenant, to collaborate on a site, library, or even a SharePoint list. For a guest user to have access to share files on your document library, they need a minimum of contribute or edit access.
However, you might spend time troubleshooting the reason why a Guest user will get the error: Sorry you don’t have access, even when they have the same contribute or edit access as an internal user on that SharePoint tenant. See below:
The reason for this is that by design, a guest user cannot Share files with others when they try to share with “People with existing access”. However, when they select the option: “People you choose”, the error disappears the document is shared successfully.
To save you the stress of troubleshooting an issue that doesn’t exist, unlike an internal user, a Guest user (someone external to your tenant) cannot share files from a document library, using the share link setting option of: “People with existing access”. Just have them use the other option: “People you choose”.
That’s a wrap,
