Error: 'Outreach SSO - Sorry, but we're having trouble signing you in.
AADSTS50105: Your administrator has configured the application Outreach SSO to block users unless they are specifically granted access ('assigned') access to the application.'
It seems your Org has SSO (single sign on) enabled, which is preventing you from accessing Outreach.
Please advise your IT admin about this. Your IT admin needs to grant you access to Outreach within the SSO setup. After that, try to log in to your Outreach account.
Your Org has SSO (single sign on) enabled, which is preventing users who were not granted access to Outreach within your SSO from accessing their Outreach account.