inbounds calls show failed in logs.

[Mirzab]

Left side menu on Admin page - Lines >> Manage - clicking on a line under "Identification" column gives different options compared to selecting same line under "Gateway/Provider Name" column. I believe you are seeking settings available under the latter column.

 

[Mirzab]

That is certainly your choice, 3CX is not mandatory. My personal opinion - nothing better unless you spend major dollars, and even then I would debate it. Maybe give it a try again after another month, v4 should be out then. I do love it myself, have it running trouble free in two locations.