My phone wont retain network while roaming? USING PAY AS U GO

[GOBMITIE]

I am abroad and have an android dual sim with O2 number.  I have just discovered that the phone keeps rejecting calls either outgoing or incoming.  To make a call I have to turn phone off, reconnect to a network.  Make a call but then when I try a second call, I get "call failed".  Using pay as u go. Got £30.00 credit.  For network I tried both automatic and manaul.

I can send and receive texts ok.   I changed the sim in early September in Enniskillen NI. I am in Ireland now.

I have tried sim in an iphone se as well and same result.

I am stumped.

[Kwak]

Same problem now in France came to light in June when over visiting family, could have been an issue for a while though. Still get 4g though, but can't make calls unless I re register on network. REAL PAIN!!
Called O2 when was in UK they said all ok, but wanted to put me on pay monthly. Am on international big bundle pay as u go.

[Milzee]

Hi, were you able to resolve this issue? I have the same problem. PAYG SIM in a Galaxy S22. 4G and SMS working fine when roaming but incoming and outgoing voice will not work. I have to try multiple attempts at manually changing network or switching flight mode on and off to make or receive a voice call. It's a different combination every time and if I want to make another call 30 mins later, I have to do it all again. I've had it in three roaming countries so not network specific. Been happening since June when I switched to O2 as Three whacked up their roaming charge to £2 per day!