After removing 2-step verification, I can no longer access my files.

Until three months ago, a two-step authentication app was registered on my company iPhone, so I used that app to perform two-step authentication, but two months ago my company iPhone was managed by MDM. Now I can't install two-step verification apps. Two-step verification is possible via SMS or email, but I didn't want to use it, so I deleted the two-step verification function. As a result, files that were previously accessible are no longer accessible with the message "This shared file or shared folder link has been deleted or is no longer available." How can I access my files again?