Coding error detected, it must be fixed by a programmer: The continue param to $OUTPUT->confirm() must be either a URL (string/moodle_url) or a single_button instance.

More information about this error

Debug info:
Error code: codingerror

Stack trace:
line 2118 of /lib/outputrenderers.php: coding_exception thrown
line 72 of /user/view.php: call to core_renderer->confirm()