What does Sage 100 have to do with a VOIP phone?

Are you connecting with the Sage server through a VPN connection?  That is not generally recommended. 

What version (Standard / Advanced / Premium)?

I said the same thing (what does it have to do with ViOP), which is the head scratching aspect of it for someone on the Blytheco helpdesk to say.

No, Everything is in house so to speak. Sage is terrible running via VPN. IF anyone that works remotely needs access to it, we have dedicated RDP workstations for them to access.

Currently we are running Standard with maybe 10-12 people using it at any given time.

Standard relies heavily on network speed, and 10-12 is on the higher side for Standard, especially if your system has a lot of data.

Firewalls do not affect Standard at all.  It is 100% functional through Windows file shares over the network.

Perhaps talk with your Sage Partner about changing to Advanced / Premium during your next upgrade, which might give you a performance boost (with the client server architecture).

I have no idea is this is what was trying to be communicated about VOIP, but this is based on my own experience.

Most VOIP phones have a network port so that you can plug your computer into the back of the phone so that you only use 1 network port per cube, desk, etc. This method of connection become problematic because you are now mixing your Sage traffic with your VOIP traffic. Best practices (at least as it was explained to me by our VOIP vendor a decade ago) suggest that your VOIP phone network should be a separate network from the rest of your nodes.

These separate networks are managed by my Fortinet, which is both my router and my firewall. Phones are on a 172.x.x.x and everything else is 192.x.x.x. If I piggyback on one of my phones for a network port, that traffic will route to any device on the 192.x.x.x network perfectly fine but I can watch it travel across the 2 different networks serviced by my firewall router. I know from experience that I have made incorrect changes that have broken or hampered that bridge and affected a devices ability AND that Sage 100 Standard is in fact slower that way when running an I/O intensive process like a 30-40 page crystal report from the Sage menu.

Anecdotally, I have also seen a phone improperly plugged in getting a 192.x.x.x because that jack used was to the 192.x.x.x switch bring a Sage 100 Standard system to a crawl at one of my customers. We traced to an extension someone had decided to plug directly to a switch in the server room.  It was an intermittent issue because the IT person was taking their phone into the server room to call for support on something else and there was no phone in there.  It took weeks to figure out and we only did because the person had left the phone plugged in and wanted to go get their desk phone to work with us trouble shooting. Happenstance we put 2 and 2 together that everything was fine when he got back to his desk.

That makes sense: VOIP phone overloading the network with traffic, meaning less bandwidth available for Sage 100 activities.

You may want to review this Sage Knowledgebase article on "Slow performance when opening a new task or starting Sage 100, or when running Sage 100 across a network" as it discusses Ping times and some other factors that can affect Sage 100 response time/performance including: "WIFI connections are not supported", and "Running Sage 100 Standard over a Virtual Private Network (VPN) and/or a Wide Area Network (WAN) or through other remote means is not supported".  

https://us-kb.sage.com/portal/app/portlets/results/viewsolution.jsp?solutionid=223924250030079&fromemail=true

Based on your statement that it seems to only happen when there are changes to the firewall, and firewall settings should not normally affect Sage 100 Standard as mentioned elsewhere here (it does not use Client/Server architecture in the same way as Advanced and does not have an application server port that could be blocked by firewall), then it could be something else environmentally is affected by firewall changes and that is affecting Sage 100 due to it slowing down network. 

You may also want to have your IT confirm the antivirus exclusions for Sage 100 too, to make sure that is not affecting Sage 100 performance - see article https://us-kb.sage.com/portal/app/portlets/results/viewsolution.jsp?solutionid=223924950045806&fromemail=true

It does actually make total sense now.

Sincerely appreciate all of the insight. Now I have a direction to go to resolve the issue once and for all.

Glad that it helped. Please report back an update what you found so the next person has more data!