Working great for months, I add a port and now my speakers are cutting in and out across the board

Since you rule out your local network as a possibility there isn't much we users can do for you.

A diagnostic and a follow-on call to support is likely your best bet.

I’m starting to see why you have 14K replies.

Seriously - this is the second time you’ve replied to one of my posts - minutes after the post - with basically a reply with nothing useful in it.   How about we wait to see if someone ELSE has ideas?   What use is you telling me ‘call support’.  You think I’m not aware I can call support?  Do you just reply to every post with ‘something’?   

I hate forums that keep reply counts or give people ‘kudos’ for merely replying.   This is why real sites have voting on replies so you don’t get noise like this. 

You can ignore the counts, I do, the profile settings even let you hide them. The silly forum counts every post, even from years ago which for long time users is a bit odd.

And yes I reply quite often, I keep the forum open in the background and check for new posts as I have time.

I wasn't implying you are not smart enough to call support on your own, without my suggestion. Go back and read what I wrote, "Since you rule out your local network as a possibility" which is very different. Users here have a decent reputation for helping but if the primary cause of issues is off the table there is little users can do.

At risk of offending you further you might ask the forum moderators to take a feature request to the forum developers to add an "ignore / hide user" option which would at least solve your issue with me. Your other forum suggestions are good too, maybe include them? 

Have you simply tried rebooting your entire network? You didn’t state that you have tried that.

As far as your access points go, are the radios set correctly to non overlapping channels?

Have you tried hardwiring a speaker or the Port to your network to see if that helps?

Because you have not provided enough information about your network other than the enterprise level APs, if none of the above works, calling Sonos support would be your best bet, as ​@Stanley_4 suggested. 

Are all your Sonos devices on WiFi?  Was the Port on WiFi before you removed it?

The other day I was helping a friend who has a large SONOS system that was having very awkward issues. He also has business grade WiFi. But, there was a LITTLE network configuration issue … .

When troubleshooting, once you've assumed that the issue must be [ … ] or cannot be [ … ], you are likely to be blindsided. If I was playing percentages, I’d bet on your network configuration causing issues, but we cannot rule out WiFi interference or a PORT hardware issue.

SONOS phone support can help.

If your system is working well without the port and doing nothing more that adding the port brings it to it’s knees, there aren’t a lot of possible causes. It’s either a faulty port or a network issue. But like others have said, you really haven’t included enough info about your set up to really help.

I suggest we leave to their own devices any posters who insult and berate those whom they are seeking out for help.  Nothing good can come from indulging in their abuse. 

I have enough problems keeping Sonos stuff in my head, trying to remember folks to avoid, well that is why I asked for the ignore-user option so long ago and so many times.

So far, like my many youthful requests for a pony, results have not been answered. On the pony, make that a hefty horse, I'm old, big and a bit chubby these days.