I tried calling Malaysian numbers, in Penang, from my mobile phone (TrueMove SIM), but get an error every time.
I tried in the usual way Protected content ... 60 for Malaysia and 4 for Penang) and then with Protected content . Then I called TrueMove's "True Care" line, and they were very friendly and quick to answer... but had no idea. They suggested adding a one after the 60 for Malaysian landlines for, for some reason ( Protected content ) but that just got me Malaysian error messages instead of Thai ones. (For one, I got through to a mailbox for an "014..." number, i.e. not the number I wanted.)
I got someone to ring the same numbers from Indonesia, and they connected ok.
And I regularly call to Indonesia from this phone, no problem.