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georgehuang · 03-05-2021, 10:02 PM

I now have Calibre Content Server running with nginx as a virtual host, which has received a SSL certificate from Certbot for security's sake. They all run on Ubuntu 20.04 on a VPS. And I also set up a startup service that runs Calibre:

Code:

/opt/calibre/calibre-server /home/ubuntu/Calibre --enable-local-write --enable-auth --auth-mode "basic" --ban-after 5 --ban-for 5 --log /home/ubuntu/log/calibre.log

Most of the time Calibre runs great, but I get 502 Bad Gateway error about twice or thrice a day. I have logs enabled but calibre.log does not show anything related. nginx's error.log do have reports like:

Code:

[error] 641#641: *1773 connect() failed (111: Connection refused) while connecting to upstream ...

This can be easily fixed by restarting Calibre server, without having to restart nginx. However, that means I will have to ssh into my VPS and run the command, which is not as easy to do when I am out with only a mobile phone.

Any idea why this might happen? Is there anything I can do to fix this?

03-05-2021, 10:02 PM	#1
georgehuang Enthusiast Posts: 42 Karma: 10 Join Date: Oct 2020 Device: MacBook, iPhone, Kindle Paperwhite	502 Bad Gateway errors on nginx server I now have Calibre Content Server running with nginx as a virtual host, which has received a SSL certificate from Certbot for security's sake. They all run on Ubuntu 20.04 on a VPS. And I also set up a startup service that runs Calibre: Code: /opt/calibre/calibre-server /home/ubuntu/Calibre --enable-local-write --enable-auth --auth-mode "basic" --ban-after 5 --ban-for 5 --log /home/ubuntu/log/calibre.log Most of the time Calibre runs great, but I get 502 Bad Gateway error about twice or thrice a day. I have logs enabled but calibre.log does not show anything related. nginx's error.log do have reports like: Code: [error] 641#641: *1773 connect() failed (111: Connection refused) while connecting to upstream ... This can be easily fixed by restarting Calibre server, without having to restart nginx. However, that means I will have to ssh into my VPS and run the command, which is not as easy to do when I am out with only a mobile phone. Any idea why this might happen? Is there anything I can do to fix this?