Ever since the 3.5.5. Update, everytime i try to sudo something, it fails.

Every time it tells me the source is untrust and corrupted, and if i want to delete it. Pressing y or n leads to thr same outcome every time, aborted install.

The same is happening when i want to update the keyring or anything with sudo.

Im genuently at a loss and dont know what to do. Please i need help