No access permissions

Drupal Guru, hello!

I have encountered the following problem. The site works fine on the local server, but as soon as I tried to move it to an external server, when attempting to make any changes, it shows the message "You are not authorized to access this page," even though I log in as the administrator user. I log in with this username on the local server as well and everything works...

Please help.

Respectfully,

Sergej