nable to access a file someone shared with you
If you're unable to access a file that you could open before, or if you can't access something that was shared with you, there are a couple of possibilities.
The file owner hasn't granted access to your account.
You were removed from the list of people with access.
The owner of the file deleted it.
If you have the link to the file or a sharing email, you can request access to it. Visit the URL, then click the Request access link on the page that says you don't have access.
If you think that you're receiving this message in error, here are some things you can try:
Make sure you are signed in to the correct Google Account — one of your accounts might have access, and another might not.
Contact the person who invited you to confirm that you have access and that you're visiting the correct URL.
If you're only able to view a file, but not edit it, you can ask the owner if you've been added as a viewer, commenter or editor.