This morning we arrived to find NONE of our phones registered to our 3CX server, but the server itself was running fine and all the lines were properly registered. After extensive testing of ports and stuff with our host (Rackspace) and no resolution, I contacted Deerfield. We are a licensed customer and had a little bit of support left on our contract. I must say, their techs were absolutely 100% top notch in helping us to solve the problem. After gobs of tests, they discovered a STUN problem (not through our configuration or anything) and advised a fix. About 10 minutes later, we were back in business and all phones were running fine. When our 3CX stops working, our business might as well be closed... To folks outside of our industry, it might not seem possible that Ferrari parts are a "rush" kind of item where the phone MUST be answered immediately. But it is. Our customers want parts fast, and don't like getting voicemail or hearing about technical problems. Our situation this morning was incredibly stressful and the Deerfield team was able to lower my blood pressure and stay 'engaged' in the issue until resolution. No passing of the buck, no blaming of another software vendor... just hard work until the issue was solved. A+. Thank you Deerfield. Now I know why the 'registered' version with real support is the only way to effectively run 3CX in a production environment.