Not receiving some texts abroad

[Mjw126]

I am currently not receiving texts from some people known to me and organisations (including frustratingly two stage verification codes) while abroad in Australia.  Texts from others including Smarty's verification code work fine.   I have the relevant off plan package and can receive calls on the UK SIM, I  have made the changes recommended to the 3 access point settings and the message centre number is correct.  I use my Smarty SIM in a dual SIM Samsung Galaxy Note 10+ with a local provider on the other SIM.  Everything worked fine before I switched to Smarty (from 3 ironically).  Any suggested solutions much appreciated.  Thanks.

[Chalkychap]

I used a similar setup when I was in Australia in 2023, @Mjw126. With a SMARTY SIM in slot 1, and a data-only eSIM in slot 2, my 2FA text messages all worked while I was roaming in Victoria. 

Given some 2FA messages work and some don't, the answer could be a simple as some organisations sending your 2FA messages without a +44 prefix to your mobile number. 

Otherwise, it could be a network routing issue. The majority of 2FA SMS messages would be sent from a computer system via an SMS gateway on to a mobile network, destined for a mobile station (i.e. handset device). SMS usage is typically between one mobile station and another mobile station, on the same or different mobile networks.