[SOLVED] mobile reported as continually engaged - Fairphone 3+ after update to e.OS 2.4 from 2.3

[swarfendor437]

After a recent OS update to Fairphone3+ family members trying to contact me were greeted with 'line busy' sound. The only temporary solution was for me to put the GiffGaff SIM into my old 1+ 3T. In the early hours of this morning I delved into the GiffGaff settings. The preferred voice call network was set to 4G, changing this to 3G got rid of the 'line engaged' issue. However, the network symbol at the top of the phone still shows an exclamation mark over the network signal icon of a right-angled triangle.