browser disconnects from pgAdmin4 server

Hi all,

I have pgAdmin4 server running on Ubuntu 18.04 server with Apache, and I
connect to it from my laptop using Firefox, which works well. One
inconvenience is that my browser's session disconnects from the pgAdmin4
server after a long time, so usually if I leave work pending at night to be
continued the next day, when I resume work in the morning pgAdmin can't be
used because it is not connected (and it won't reconnect). My work-around
is to copy any open queries to a text editor, refresh the page, sign in to
pgAdmin, and open new tabs and copy the queries back from my text editor.
Of course, any temporary tables are lost and I must also recreate them.
Does anyone in the community know how to make sessions last longer?
Perhaps there is a setting in one of the pgAdmin config files or Apache?

Thanks,
Gabriel