I have external access enabled on a site collection in my tenancy, and was previously able to invite external users to the site successfully, but now when I attempt to add external users nothing happens.

I don't receive any error messages, so it appears that the invitation has sent, only the user never receives the email. When I go to the Access requests and invitations page they are not in the External User Invitations list.

I set up a dummy Outlook account and was able to grant access to that user, but other domains aren't working.

However, I have added users from other domains in the past, so I can't understand why it worked for some users and not for others?

  • are you passing any custom message with invite ? Apr 22, 2016 at 13:27
  • Short answer: You can only invite addresses connected to a live-id Apr 22, 2016 at 13:27
  • Not quite true, you can invite any email address, but they must authenticate with a Microsoft account (live, outlook, etc) or Office 365 account. Apr 22, 2016 at 13:31
  • @EricAlexander is right - you can invite them and later on they have to create or link a Live ID to the account so they can access the site. But in this situation the invitation is never created.
    – jber
    Apr 22, 2016 at 13:38
  • @BhaskarDhone I am passing on a custom message in the invite - would that make a difference?
    – jber
    Apr 22, 2016 at 13:50

1 Answer 1


In SharePoint Online external access invitation will not get sent if invite message length is more than 255 character.

If you provide invite message with more than 250 character and invite. It closes window like invite has been sent but it will not send. Apparently , Microsoft has not provided any validation for it.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge that you have read and understand our privacy policy and code of conduct.

Not the answer you're looking for? Browse other questions tagged or ask your own question.