How can I find out what the firewall issue is on a Printer?

I was having problems reinstalling HP software for my All-In-One printer,
and HP Tech support had me add ten or fifteen programs to the Firewall as
allowed programs, plus about that many ports. I'm still having firewall
issues according to the HP networks diagnostic tool, and the HP software
does not "see" my printer on the network.
I can go to its IP address in Internet Explorer and see info about its
status, etc, and I can install basic drivers for other similar printers and
it will print, but not from the Full Software package that I need for OCR
scanning. It is listed under Printers and I can print a test page.
The HP Diagnostics has a AutoFix button but it doesn't fix the issue, and
doesn't say what is wrong. Until I had problem reinstalling the software it
had worked fine for two years.
How can I find out what the firewall issue is?

 

Does it work if you turn off your software firewall?

If not - it's not a firewall issue unless you have some other firewall
between you and the All-in-One.

 

I will try that, but I hope that is not the answer - I don't want the
firewall off permanently!

 

Shenan Stanley's suggestion was for a *test* to isolate the problem.

You might also want to (temporarily) disable your router's firewall as a
second test.

 

Turning off the firewall made no difference.

The printer works with the original software from another PC.
It prints if I use generic drivers, but won't scan OCR.
It was running fine for two years before the software got corrupted and I
got fatal errors reinstalling it. I have updated software from HP but
firewall issues.
So how can the firewall block it under some software and not under others?

Back to my original question - how do I find out what is blocking it? The
HP Home Network Diagnostic Utility says "Network communication is not what
was expected. A firewall is still blocking communication." It says this
whether the firewall is running or not.

 

I am not sure how to check firewalls in Sophos AntiVirus.
However at one point I did turn it off and that made no difference.

 

HP is famous for crappy software when any bi-directional communication
to their printers is involved. They're also famous for not fixing the
problems when they occur, especially when an OS update breaks things.

You can try shutting off your A/V just for testing and see if it
helps. My guess is that the HP software is having a communication
issue and is throwing the "firewall" message as a generic response to
any communication problem.