How many traffic and request does Xray-Core can handle ? I'm getting errors

[AghaFarokh]

Hello everybody and I hope you are doing well

I'm running xray-core (x-ui) behind nginx and just nginx is just doing reverse proxy, sending requests to the xray-core
now I'm facing some errors on the nginx log like
connect() failed (111: Unknown error) while connecting to upstream,
or
recv() failed (104: Unknown error) while proxying upgraded connection
I did a lot of nginx config and tests nothing happened, somehow I think maybe it's not related to nginx and xray-core can't handle this many connections
btw this is my problem I'm getting 150MB of error.log every day and I did a lot of nginx config tuning
pls, tell me what are the maximum xray-core requests handling. and is there any way that I can fix this problem or do I need to reduce the number of users on the server? because I don't facing this problem on servers with a lower users

[AghaFarokh]

I need to add that my config is working and there is no problem in the connection, clients are connected to the server but there is a lack of quality that I think it's because of these errors
I can add logs and configuration if u need to check