@Ciaran Mallory Thank you for reaching out to us, in order to troubleshoot this error AADB2C90304 "selfassertedsigninname" need to review custom policies configuration in detailed, would suggest to open a support ticket with us to troubleshoot further if in case you don't have a support contract let me know we enable one time support option on your Azure subscription for this issue.
Azure AD B2C error when tab is closed without logging out and attempting to re log in in same browser session
We have an application that is using Azure AD B2C custom policies for sign up and sign in flows. Users are experiencing an error which appears when a logged in tab is closed without logging out and then attempting to log in in a new tab in the same browser. This issue only appears in our UAT tenant and not in DEV, QA or PROD. I have attached the error message. This issue also persists in an incognito browser. I am wondering if anyone has experienced this before I open a ticket. Any guidance would be appreciated.