Softphone issue

I recently had to replace my router that went bad. Whenever I have a softphone up and running on my computer, both the 3cx softphone and the voipo phones ring just fine but the problem I have is which ever phone I pickup first the other phone continues to ring. The call works fine with either one just the unwanted ring from the idle phone. Im sure the issue is with this new router because I never had this problem with the other one. Hoping someone may know what may be causing this. Thanks for any help.