External Users cannot share SharePoint sites with other External Users: "Sharing failed: The user has insufficient permissions to create an invitation."

Question

When an External User who is a member of a SharePoint site tries to share the site with another External User he/she gets the error message "Sharing failed: The user has insufficient permissions to create an invitation."

However, the same External User can share the site with a licensed Internal User without any problems.

Here are the facts:

• In the recent past External Users were able to share sites with other External Users.
• The external user is a member of the SharePoint site's default group
• The "Allow members to invite others to the site members group" checkbox is checked for the site.

Why is this new behavior occurring and how do I resolve it?

Answer 1

Hi Scott,

Sorry for my late reply.

I notice the site is a classic team site, not a modern team site. So, I tested it again, and I can reproduce the same situation when External User A shares the site with a new External User B.

Based on my test, currently, only the internal user or the external user with Full Control permission can share the site with a new external user. I have searched a lot, but I didn't find any settings that can change this behavior.

Based on the situation, I would like to suggest you contact your admin or IT department to raise a support ticket via Microsoft 365 Admin Center> Support> New service request. That support team there has the correct channel to help you investigate more and find what exactly the reason has caused this situation.

Appreciate your understanding and patience.

Sincerely,

George | Microsoft Community Moderator

Answer 2

Sure! Here's some screenshots demonstrating the behavior:

1. I have a SharePoint site called "2023 HTCC test Members"
2. External User A (John Jingle) is a member of the default group for the site. (All members of the site's default group have Contribute Permissions.)

3. External User A visits the site, clicks the "Share" link in the upper right, and attempts to share the site with a new external user.

4. After entering the email address of a non-licensed user, External User A gets the error "Sharing failed: The user has insufficient permissions to create an invitation." However, if External User A enters the email address of a licensed user, the sharing goes through.

5. This is new behavior. My company has built a solution around the idea that external users can invite other external users to various SharePoint collaboration sites and it has worked flawlessly for years.

Answer 3

Hi Scott,

Thanks for posting back.

Just to clarify, Microsoft provides two kinds of accounts, Microsoft account (personal account, like ******@outlook.com) and Work or school account (business account, like ******@tenantname.onmicrosoft.com).

Based on my test, if all information you provided is correct, not like the internal user with Edit permission, External User A with Edit permission should not be able to share the site with others (he won't see any options that can make him share the site in the site interface). Only when External User A has Full Control to this site, he can share the site with another external user.

As you mentioned External User A is in the Site Member group, it should be expected behavior that he can't share the site with others. Unless External User A not only has Edit permission but also has Full Control permission to this site before.

Since you also mentioned it worked well before, I would like to collect more information to better troubleshoot the situation.

1. Please share a full screenshot of the error message.
2. I would like to know how External User A shared the site with External User B. Did he manually share the site (like Site Permissions> Advanced permissions settings> Grant Permissions) or use a customized SharePoint app? Based on my search, here is a thread where members mentioned a similar error message, and they used a SharePoint app to share the site.

If External User A manually shared the site, please share the detailed steps about it.

We look forward to your response. Thanks for your cooperation.

Sincerely,

George | Microsoft Community Moderator

Answer 4

Hi George!

Yes. The message appears on External User A's side.

External User A is linked to a Personal Microsoft Account.

External User B does not have an account yet. (In other words, External User B should receive a Site Sharing Invitation email that will force them through the process of creating a new Microsoft Account. and linking it to their email address.)

This behavior is consistent for any external user sharing with External User B.

Answer 5

Hi Scott,

Thanks for posting in the community. We are happy to help you.

According to your description, when External User A shared a site with External User B, the error message popped on. To better troubleshoot the situation and test it, I would like to collect more information.

1. I assume the error message appeared on External User A's side. If not, please point it out and let me know.
2. Is External User A's account a Work or school account (business account) or a Microsoft account (personal account)?

 Is External User B's account a Work or school account (business account) or a Microsoft account (personal account)?

3. If there are other external users who are members of this site, does the situation happen again when they share the site with External User B?

We look forward to your response. Thanks for your cooperation.

Sincerely,

George | Microsoft Community Moderator