Why can't I use my phone overseas

I have an fairfone 1, am overseas, can’t get it to pick up a local service provider. I am on Orange 02.
There is a symbol that looks like a lock on the service grid thing at the top of the screen. If it is a lock that prevents the sim picking up a local service provider I can’t find out how to unlock it. I’ve never had this problem before, my phones have always just connected with a local service when travelling. Can anyone help please. Thank you.

In which country are you?

I am in south west Ireland.

This should help you: Go to Settings > More… > Mobile networks > Providers/Operators > [Choose your SIM, in case you use Dualsim] > Choose automatically.

If this does not help, then Choose manually and let your phone search for networks. Select one of the found networks. You should receive a text message telling you the communication fees.

PS: Translations might be slightly different, my settings are in German.

Thank you. I had tried both of these, a number of providers are identified but I cannot connect with any of them. As soon as I try to the little ‘key’ symbol appears over the sim strength symbol at the top of the phone screen. I am beginning to suspect that this is a problem with my own service provider and that I am not going to be able to sort it out until I get home. If you have any idea why that little ‘key’ symbol should be there do let me know. Thank you again. Linda

You should be able to get a signal in South West Ireland.
Asking for the obvious, did you enable your subscription with your provider for use abroad?
I guess that working on wifi is good.

I suspect that this must be a problem with my sim provider and I will have to wait until I am home to sort it out. Thank you for trying to help.

In my account with my provider I can enable and disable use of my phone abroad myself.

Have you already had a look at your account on your provider’s web site? Normally there’s an option to enable/disable roaming.

Thank you Irina, you were right and this was an issue with my SIM. Now solved.

Thanks again