Dual Sim not working

[Organum]

I have 2 sims on my S21 Ultra but cannot get both to work together.

The option for dual sim is greyed out.

I can change between sims but when I select one the other is cancelled. 

Ideas?

Thanks 

[Organum · Accepted solution]

Sorted but strange.

First I tried my wife's sim. Just the same.

When changing back I noticed that the S21 has a 2 sided sim card holder. I had been putting the sim in sim2 and the esim on the second provider was esim1.

I then put the sim in sim1 position and bingo  both sims could be switched on and both worked just fine. 

What a fantastic system!