what does "upstream timed out" error mean?

[baijianpeng]

After a long time observation, I noticed that ALL above settings had not healed this issue. Because I still can see this error message in my log file:

... upstream timed out (110: Connection timed out) while reading response header from upstream, ...

(It is interesting that it was in the log file /var/log/apache2/domains/domain.error.log instead of Nginx error logs).


Yestoday, I found another kind of answer for this issue on stackoverflow.com:

http://serverfault.com/questions/647411 ... out-errors

Do you think this is the solution? How to apply it to VestaCP?

Thank you.