Hi, We use 3CX with Cisco SPA504G sets. Everything works Fine, but I found that when I restart the 3cx phonesystem in services status, that some extensions take 10 to 15 minutes to re-register. In extension status it shows as red , until it finally registers, then shows green. This never happened previously. The 3cx version used is 12 and service pack 6 Firmware used on most of the SPA 504G is 7.5.4 and some 7.5.5 and 7.4.2 Thanks in advance for any suggestions.