In that case I suggest you to kindly re-enable Google Drive settings for file sharing and cloud file storage options for the file tab.
To do so: Open Teams Admin center > Org-wide settings > Teams settings > Files > Google Drive Om/Off
Change your network (make sure there is no firewall or Antivirus blocking Teams) and check if you are able to upload your files. Use Teams online app and check if you are able to upload such files from Google drive.If the issue persists, please try the Teams on the web side. Also run the browser in private mode to check it.
Thanks and regards,
Josephine J.
Yeah! I tried all probabilities but was of no use. I contacted Microsoft Support. I was informed that there was an ongoing issue with it and they are working on it. I will be notified when it is done.
Anyways thank you for your support and concern. Thanks once again.