Problem: I created 10 AlwaysOn Availability Groups with SQL Server without a problem. Suddenly, it stopped worked and I kept getting this ONLY on the "create the listener" part:
Msg 19471, Level 16, State 0, Line 9 The WSFC cluster could not bring the Network Name resource with DNS name 'L_MyListener' online. The DNS name may have been taken or have a conflict with existing name services, or the WSFC cluster service may not be running or may be inaccessible. Use a different DNS name to resolve name conflicts, or check the WSFC cluster log for more information.
Sometimes I also got Msg 19476. This was all maddening because one moment I was creating listeners and availability groups, feeling like a guru, and then everything stopped and I lost hours of time.
So how do you solve this? Of course, Microsoft's own suggested text in the above error description was NOT helpful.