Maxim Dounin Wrote:
-------------------------------------------------------
> Do you see any other errors on the same connection before the
> SSL_shutdown() error? As suggested previously, somethig relevant
> might be logged at the "info" level. Note that seeing info-level
> error messages will probably require error logging to be
> reconfigured, much like with debug.
>
> If there is nothing, I'm afraid the only solution would be to try
> to catch a debugging log related to these errors. As previously
> suggested, this can be done without too much load by using the
> debug_connection with relatively large CIDR blocks and waiting for
> the error to happen from with a client from one of these blocks.
>
> --
> Maxim Dounin
> http://mdounin.ru/
> _______________________________________________
> nginx mailing list
> nginx@nginx.org
> http://mailman.nginx.org/mailman/listinfo/nginx


Good day.

I've change log level from notice to info and there's indeed one new message related to HTTP/2 problem.

2020/08/20 15:59:31 [info] 32305#32305: *1982005 client timed out (110: Connection timed out) while processing HTTP/2 connection, client: XXX, server: XXX:443
2020/08/20 15:59:36 [crit] 32305#32305: *1982005 SSL_shutdown() failed (SSL: error:1409F07F:SSL routines:ssl3_write retry) while processing HTTP/2 connection, client: XXX, server: XXX:443

I don't know if this will help.

Regards,
Alexander.