Drupa 7. Why the error occurs: “Invalid selection made. Please contact the site administrator."?

Question

Drupal

When trying to change / add administrative permissions to a user (or create a user with the administrator role), an error appears:
“Invalid selection made. Please contact the site administrator."
In the log messages like:
"Type: form"
"Invalid selection in element 4"
"Location: https://example.ru/admin/people/permissions"
"Reference source: https://example.ru/admin/people/ permissions”
What has been done:
access rights updated
cache cleaned
google - did not find any information
What could be the matter? Where to dig?
Druoal 7 on VPS under Ubuntu 16

Answer 1

There is no universal solution, run under the debugger and see what's wrong with the form.
There are many reasons why this error may occur. Most often because of custom modules with crooked form alters or a kind of AJAX. Just recently I fixed the same because of the admin_views module and hook_views_* curves. It is also possible that you have a backdoor and in this way it "protects" itself.

Answer 2

issue resolved drupal.ru/node/133622. I apologize for not closing this question on time.