I own a Sony Xperia Z5 dual SIM phone. Phone is unlocked and running Android 5.1.1
I always used it with the same SIM card (3 Network) and it always worked well. Yesterday I tried to add a new SIM card (Vodafone) in hope of using both SIM cards in my dual SIM phone. Unfortunately the experience resulted in only the Vodafone SIM working. 3 Network SIM stopped working and now even after removing Vodafone SIM it still doesn't work. When I say "doesn't work" I mean that I can see "emergency calls only" displayed on my screen.
What I tried: -Reboot and hard reboot (yellow button near SIM slot) -3 card still works in another handset -Vodafone card works in this and in another handset
Clearly SIM card slot is not damaged seeing that Vodafone card works and 3 SIM card must be fine as well because I tried it in another phone. Phone cannot be SIM locked because I used 3 SIM card there for months or could it got locked somehow?
What should I do to make my phone work with my old 3 SIM card again?