Hi guys,
Here is the latest update.
I called 1506 and there was really a person speaking more than decent English.
I said I could log in through their website but not by using their app and this is what she explained:
The app used before was called SSO Connect and it is sunset (I can confirm this because I used it in the past)
There is a new app to be used and it is called SSO Plus, however, it only recognizes Thai ID cards for now (photo of ID card needs to be taken for initial verification)
SSO Plus app is still under development and it will support the option of foreigners using it with their pink card (I didn't ask when this function will be ready)
So for now, we use their website.
Cheers!