I installed the yith memberships premium plugin, everything is correct, but when the user buys a subscription, the site crashes and gives error 500 and this part does not open, but when the subscription is deactivated or ends, this The part is activated and opened, I also have this error in inspect and load status failed)net::ERR_HTTP_RESPONSE_CODE_FAILURE and the consumption of RAM increases sharply

I disabled all plugins, changed the theme, upgraded the RAM to 3 GB, but the problem was not solved