intermittent issue in SharePoint for external user - Guest user is signing-in but external sharing is disabled

Question

Hi,

I have a SharePoint Online site which is used to share information, and provides a communication channel to a number of external users. There is a number of these sites set up for various customer companies and currently this issue is only occurring in one of these.

The external users are added into a security group into our azure ad and this security group is added to the members group in the related SharePoint. When using the check permissions function in SharePoint I can see that the affected users have edit permissions through membership of the members group.

The issue does not present itself continuously, rather they tend to only encounter the issue randomly during the day while actively engaging with the portal, for example when filtering a SharePoint list for information.

The prompt displayed through their browser is as follows.

After being presented with this error, the user can reload the SharePoint site, can authenticate and work as normal.

Answer 1

Dear Micha Hesemans,

Good day! Thank you for posting in Microsoft Community. We are glad to help you.

According to your description, guest user is signing in a SharePoint site but external sharing is disabled, the situation appears randomly.

As you mentioned the user can reload the SharePoint site and can authenticate and work as normal, it looks like the user's permission to the SharePoint site is correct.

For troubleshooting, you may let the user try to clear browser cache and try a different browser to see if same situation still happens.

On the other hand, we would like to confirm the following information, it will help narrow down the situation. Thanks for your patience and understanding.

1.Does the situation only appear in a specific SharePoint site?

2.Does some specific external users or all external users encounter the error message when they work in the SharePoint site?

We look forward to your reply. Appreciate your understanding and cooperation.

Hope you are keeping safe and well!

Sincerely,

Tina | Microsoft Community Moderator

***Note: In the event that you're unable to reply to this thread, please ensure that your Email address is verified in the Community Website by clicking on Your Account Name > "My Profile" > "Edit Profile" > Add your Email Address > tick "Receive email notifications" checkbox > click on "Save".***

Answer 2

We are having a very similar issue. It's been happening for the past two weeks. It's only been reported by one group of two external users from the same company, but these users have been successfully accessing this site for several years now (they're from a large auditing firm). The message is very similar... That didn't work External sharing is disabled for ....

The reference to what the external sharing is disabled for is something that doesn't appear related to the site they're trying to access (/appCatalog/.... )

The users are always just clicking on the one link. The link takes them to a folder in a library in ONE site. The link never changes. The access should always remain the same. Yet in the past two weeks, they've struck problems frequently enough to be a hinder to business. I'm not aware of this happening on other sites or to other external users.

Answer 3

Dear Dan O'Callaghan (Admin),

Since you mentioned the external users have been successfully accessing the SharePoint site for several years and the situation is happening recently, we sincerely recommend you create a support ticket from Microsoft 365 admin center>Support>New Service request. The support team over there has higher permission than us. They can remotely help you and have more resource to check the site and collect log when the external users cannot access the site. This would be a more efficient way in handling the case for you.

For reference:   Get support | Microsoft Docs   How do I find my Microsoft 365 admin 

We appreciate your patience and understanding!

Sincerely,

Tina | Microsoft Community Moderator

***Note: In the event that you're unable to reply to this thread, please ensure that your Email address is verified in the Community Website by clicking on Your Account Name > "My Profile" > "Edit Profile" > Add your Email Address > tick "Receive email notifications" checkbox > click on "Save".***

Answer 4

1.Does the situation only appear in a specific SharePoint site?

Yes, this is affecting one external user in a specific SharePoint site.

2.Does some specific external users or all external users encounter the error message when they work in the SharePoint site?

There is only one specific external user that is encountering the error message. They receive the error message during an active session when filtering a SharePoint list, they generally are able to use the same exact actions in the same list without issues. The issue seems sporadic, or might be triggered only in very specific circumstances.

Answer 5

Hi Micha Hesemans,

We appreciate you post back and share these detailed information with us.

For further troubleshooting, we'd like to share following suggestions:

1.Let the affected external user use private window of browser to access the SharePoint site.

2.As the error message appears when the external user filters a SharePoint list, you may check if there is any item in the SharePoint list which has unique permission and whether the external user has permission for the item.

You may open the SharePoint list, click Settings>List Settings>Permission in this list,

on the permission page, see if it says "some items of this list may have unique permissions which are not controlled from this page". if yes, click "Show these items", it will show the item, you can click "manage permissions" to go to the item's permission page, then check if that external user's permission.

3.We checked service incidents from our side but didn't find any on-going incidents related to external user cannot access SharePoint online.

There were service incident SP392598 and SP392504 which user impact is External users can't access SharePoint Online sites shared by users through links or a direct URL.

You may go to Service Health Dashboard with admin account and check if your tenant is still affected by this service incident.

However, if same error message persists after you check the suggestions we shared above, for further investigation, it may need to check his account from back end. So we recommend you raise a support ticket from Microsoft 365 Admin Center>Support>New service request. The support team over there has more resource to help you investigate the situation further. This would be a more efficient way in handling this case for you.

You may refer to Get support | Microsoft Docs   How do I find my Microsoft 365 admin 

Thanks for your cooperation and understanding.

We hope you have a nice day!

Sincerely,

Tina | Microsoft Community Moderator