Dear All,

On my SL7.4 laptop, I have docker-pr listening for https connections.
(Within docker, I have a locally-compiled copy of elabftw running an
electronic lab book service.)

When I point my web browser (Firefox) on the same machine to
https://localhost, I initially get a "Your connection is not secure"
warning.  That's not surprising, because my certificates are not
signed by anyone else.  So, I choose the "advanced" button then the
"add exception" button (with "permanently store this exception"
unchecked) to go ahead and connect.

After this, all sometimes works smoothly - I arrive at the elabftw
login screen and can carry on and use my electronic lab book.
However, on other occasions, I get the message "502 Bad Gateway:
nginx" and am unable to connect to the electronic lab book.  I'm not
aware of having done anything differently in the two types of case.
Doea anyone have any idea what might explain the two different
behaviours, please?

Thanks,

Dan