@bm3 Check if your public IP was voip blacklisted. Alot of attempts could cause this. If so change your public ip. test tool (voipbl dot org)

@bm3 I am using ER8411 with Omada Controller. State Time Outs are located under Network Security --> Firewall. I put 3700 sec for almost all. Typically disabling SIP ALG is the only thing you need to...

@bm3 I had to raise the State Timeouts on the firewall to allow sip registration to keep alive. My yealinks are set for 5 min. Be sure the timeouts are set for longer. I also have flood defense...