Why does the server stop responding after starting the nuxt server?

Question

Apache HTTP Server

Kontsiguration such
Front on nuxt and api on php on the same host everything is twisted under the apache.
Already running and spinning 5 other front modules on nuxt via pm2, all on different ports and subdomains.
nuxt connects to api on localhost when server rendering.
There is also the 6th module, it has the most users, as soon as I launch it, requests begin to pour on it, to which it successfully responds at first, and after a couple of minutes all modules and all subdomains stop responding altogether.
it is worth disabling this sixth module, as all other subdomains are immediately loaded.
in general what to do? it doesn’t smell like a highload, the maximum requests are 30-50 per minute, and the server gets cancerous and it’s not clear for what reason and how to debug it.
I'm looking for advice and guidance.
in htop and pm2 list there is no visible load during slack, the server just stops responding. can somehow configure proxypass for hosts in a special way?