Sharepoint External Users Cannot Access Two Sites at Once

Question

We have a Sharepoint site that is shared with external users, and one subset of users is unable to access the site reliably.  They also have their own Sharepoint site set up for their own organization, and report that when they access our site, then try to access their Outlook email or their own site, they are logged out.  When they log back in to access their Sharepoint or email, they are then unable to access our site without a new invitation.  Is there a reason this would be happening, and what can we do to resolve it?  Thank you for your help.

Answer 1

Hi JBSFM,

Sorry for the inconvenience caused by this issue.

Here are my test steps, please have a look:

1.Access my site and click the Share button then type account to share my site with an external user.

2.Sign in Office portal with that external user's account then move to the mailbox and click the notice mail to access that site.

3.Move to that external user's own SharePoint site and I can access both sites normally.

4.Close the sharing site then click the site name in invitation mail again to access the sharing site.

If it that your scenario? If so, to check if this issue is browser cache related, please sign out all Office accounts then clean browser's cache to check if your external user can access both sites normally. Please also try other browsers to see the outcome.

Please have a try and share with me your results.

Regards,

Neo

[Updated by Neo Wu MSFT, Mar 15th, 4:06 PM(UTC)]

Answer 2

Thank you for your reply.  I am sorry, I am unable to log into their Office 365 account, as they are a completely different business.  We have several external users from different businesses accessing the site just fine, but this one particular business is unable to access both our site and theirs without being prompted to log out.  Is there another possible solution?

Answer 3

Hi JBSFM,

Does your external user access your site and her/his site normally now? Do you still need any help?

Regards,

Neo

Answer 4

Authentication is generally a disaster in SPO. Msft needs to spend time fixing important things like this and stop futzing around with things like the "modern" ui that no one asked for or wants.