Hello @Sagar Chaudhuri
Thanks for your question.
You're likely to receive this error "That didn't work" when you are using the portal for the first time.
You will need to send an email to SaaSApplicationIntegrations@abdou .microsoft.com (Azure AD SSO Integration Team) stating that you'd like to use '******@hifives.in' for submitting application request.
The team will then add the account in the Microsoft Application Network portal.
You could refer this article for more information.