Error validating client secret
I had recently enabled external access for site collection on the SPO tenant only to selected domains and authenticated external users.External sharing in Share Point online works well in most scenario’s but there are few issues which pop up while enabling access for external user’s and with limited error details it becomes a bit challenging to understand the cause.
First check to make sure the account which is used to accept the email invitation to the site is the same account which is being used to login later.
Microsoft Graph is the evolvement of API’s into Microsoft Cloud Services.
For me not being a developer, a key difference is interacting with with Graph API using OAuth 2.0 via Power Shell.
Secondly if theaccount used for accepting the invite and login are properly set and still the error screen pop’s up, then user account has to be set up again, but before clean up the existing references and remove the user from Share Point and then send fresh invite.
To remove the user and all references follow the below steps.
Secondly if the account used for accepting the invite and login are same and still the error screen pop’s up, then user account has to be set up again, but before we do the clean up on the existing references for user profile and remove the user from Share Point and then send fresh invite.