Origineel bericht door: Tom Chai ,
This could be either due to carrier or the phone, or both. Likely scenario 1: * Carrier do not support VoLTE, or the service is not enabled on the number/device, therefore CSFB is needed. * The carrier’s 3G service is deployed on a band or technology that the phone does not support, or it technically supports, but broken. Likely scenario 2: * Bad carrier provision, which resulted in non-standard signaling behavior that happens to be not supported by this device, or its specific baseband software version. Since no specific carrier or device model is mentioned, no cross-testing of various carriers and devices has been performed, we can only guess now.