I'm trying to login to Salesforce by Implicit Flow using third-party OpenID Provider on localhost.
After authentication and authorization on the OP, it responds Access Token and ID Token to Salesforce, but Salesforce redirects to the error page as follows,
https://example-dev-ed.my.salesforce.com/_nc_external/identity/sso/ui/AuthorizationError? ErrorCode=No_Oauth_State&ErrorDescription=State+was+not+sent+back#access_token=eyJ...& scope=profile+email+openid& id_token=eyJ...& state=Lu5...& token_type=Bearer& expires_in=600
I'm using Connect2id server 2.3.2 as OP. It seems that the OP sent back the state value which is same as one received from Salesforce with Authentication Request.
Security Control | Auth. Provider | Authorize Endpoint URL is set as follows,