Strange mobile network problem during calls ZenFone 5z
Since a couple of months I have a strange issue with mobile network connectivity during calls.
Very poor or no mobile network at all during calls. Contacted the carrier who talks about VoLte that needs to be activated. Can't be that because there was no problems a couple months ago. I finally received a sim card with only mobile network on which I inserted in SIM slot 2. In settings for mobile network I chose that SIM 2 should be used. Calls, sms only on SIM 1.
Mobile network still disappears during calls. I don't get it. What is wrong? Hardware problem? Or software? Even tried the setting with dual SIM cards and the VoLte option for SIM 2. No difference.