Hi, I'm Sergio, it's a pleasure to help you.
If you are using the Team web app, you will need to clear the cache and cookies.
If you are using the Team desktop app, you need to remove all cache files.
To delete all cache files, you follow this steps (in Windows):
a. Fully exit the Microsoft Teams desktop client.
b. Go to File Explorer, and type in appdata\Microsoft\teams and remove all the content.
c. You must restart the app and try again.
If the problem continue:
a. uninstall the Team desktop app.
b. Go to File Explorer, and type in appdata\Microsoft\teams and remove all the content.
c. Reboot the computer and install the Team desktop app again.
Greetings.