Ultimate SEO and phpBB Gallery - how to set up?

I installed Ultimate phpBB SEO Friendly URL and phpBB Gallery. But the gallery does not open. When I go to the link to the gallery - the main page of the forum opens. This is probably due to the incompatibility of these mods.

How do I fix this?

phpBB 3.3.11
PHP 7.4
Theme: Prosilver