Sim 1 card poor signal

[paul_round]

I have recently switched over to o2 from Three, due to poor signal.

My three sim was in slot 1 and my new o2 sim was in slot 2 until the switchover was completed.

However, when my number was ported across, I took the new o2 sim from slot 2 and put it into slot one and my signal dropped from full bars to one bar. I replaced it back in slot one and I get get full signal again.

Has anyone else seen this with their phone?

I'm now beginning to wonder if I did indeed have an issue with three's signal and it was just my sim slot.

[Easty]

I've had issues with 4g dropping out when making / receiving calls , can't access Internet, maps etc .
Tried new sim , factory reset , they sent me new settings , still the same , next step is for them to disconnect then reconnect my line , I've just swopped into sim 2 tray after reading your post and see how I get on tomorrow as I've had other network sims ( ee , three ) and they work fine , I'm on vodaphone and getting fed up with it !

[BandOfBrothers]

Thats a conundrum and yes it could be the sim slot tray @paul_round 

I'm using a different phone to you as per my signature below. 

Weirdly enough I get a better service with my o2 sim in sim slot 2 and my ee sim card in sim slot 1. 

Both give me full connection however. 

[DiegoJArg]

Hi, I have the same problem with Samsung S20 5G. I was just blaming my new prepaid plan in lycamobile, but after putting my good verymobile on the first slot I got a reduced or non connectivity. While slot 2 works for both. Now I wonder if it is possible to improve slot 1 to make it work