Forum Discussion
Allowing External Users access to O365 SharePoint Site
All: I need to allow access to an external user. I have taken the following steps: 1) Shared is enabled on the site collection: "Allow external users who accept sharing invitations and sign i...
Mark, there could be several reasons for this behavior. Assuming that you sent the invite to some kind of external address (i.e. gmail.com), the user has to authenticate into your environment using Microsoft domain email address. In other words, if they try to login using same email address you shared with, it might fail, They have to login to your environment with any MSFT domain address like outlook.com or hotmail.com, live.com, etc. There could be other reasons. but this one is most likely. Also, check out this post, it provides detailed instructions on how to configure external sharing, see if you are missing a step.
Greg