Threads Says My Account Cannot Be Found

Today, I tried to log back into my Threads account, which I created years ago, using the iOS app, but I have been completely unable to access it. Even though I enter my username correctly, the app repeatedly displays the message “Check the information you entered and try again” on the “Find Your Profile” screen and fails to locate my account.

The app redirects me to Instagram to log in. However, when I try signing in through Instagram, my account still cannot be found, and the system behaves as though my account never existed. As a result, I cannot access my existing account and have effectively lost access to an account I have used for years.

I request that Threads locate my old account and restore access to it. If that is not possible, I expect a clear explanation and a practical solution that will allow me to register again or regain access through my Instagram account.