On June 12, 2018 Twitter made a change in the way they handle callback URLs used for logging in to Twitter.
This directly affects how Azure AD B2C interacts with Twitter. And right now you have to make a quick change in order to keep things working.
You need to make a quick change to Twitter in order to keep signing in with Azure AD B2C with Twitter
- Go to apps.twitter.com and click on your application that is setup as an Identity Provider for Azure AD B2C.
- Click on the Settings tab.
- Paste the following into the Callback URL field:
AND EVERYTHING NEEDS TO BE LOWERCASE!!
You can get the TENANT-NAME from your Azure AD B2C portal.
You obtain the SIGN-IN-SIGN-UP-POLICY-NAME from the policy that uses Twitter as its identity provider.
Add a callback URL for every policy you have using Twitter as an identity provider
Add a separate callback url entry for each sign-in/sign-up provider you use. AND IT'S LOWERCASE!
That's it - things will start working again.