How to solve the You don’t have access to the org in Teams error message?

Step 1: Sign into Office 365 admin portal via https://portal.office.com

Step 2: Click on Admin icon and navigate to Users > Active users.

Step 3: Select an user from the list of users.

Step 4: Switch to Licenses and Apps and scroll down to the Apps section.

Step 5: Check the checkbox respective to Microsoft Teams.

Step 6: Click on Save changes.