I have a Samsung 3G Network Extender. It has worked great for about 2 years. A few weeks ago it started having problems. About half the incoming and half the outgoing calls are dead lines. Outgoing does not ring on my end, but whomever I am calling is getting the call. Our link is dead, like putting a book up to your ear. Nothing. Incoming calls are about half dead the same way. All lights are blue, everything is in the same place as before, and I can stand 2 feet away from it and it acts the same.
What kind of phone do you have? Does the same thing happen with other phones (guests at home)? Do you have WiFi calling activated by chance? What if you dial #48 to see if it is using the Extender? What if you power OFF the Network Extender, does your phone pick up an outside signal that might have become more powerful? Has anything changed regarding your Internet access, ISP or router?
I am having the exact same issues with my extender which is also a Samsung 3G model. We have had the same extender in the same location with no problems for several years. Just recently both my wife and I have had the same issues with both outgoing and incoming calls. You attempt to call out and it takes sometimes multiple attempts to complete a call, sometimes it just hangs up without connecting, sometimes it shows that it is connecting but never rings and no one on the other end but they will tell you they received the call and were speaking. On the incoming calls you can answer but no one is there, this may happen 3 or 4 times in a row with the same person and they hear you! This has become extremely frustrating for us because we both work from home. We both have iPhones 6+ and 7+ and have done the #48, restarted the Network Extender, powered the phones on and off, to no avail. We have no signal where we live without the Extender so signal issues cannot be the caused. I am not sure but I believe it may have began around the time of the iOS upgrade to 11 although I cannot state that for a fact. Any help would be really appreciated!
We all have iphone5's. It seems all iphones have this problem. I do not know anybody with another type phone, so cannot test others. #48 works the same as calls, I can be standing 2 feet away and it will work one time, the next it will not. I have rebooted the extender, tried everything. With the iphone5, I do not have access to internet calling like the newer versions.