It looks like error code 53003 in teams is due to a conditional access policy. Consult with the business' IT administrator to check for Azure Conditional Access Policies that are applying to you and your account.
How to troubleshoot Conditional Access Policy problems
Related articles
https://www.reddit.com/r/Office365/comments/r0lheb/teams_access_issue/
https://tejinderrai.org/2020/07/16/aadsts53003-blockedbyconditionalaccess/
---------------------------
If this helps please mark as correct answer.