The way the mobile operator handles the data SIMs has changed - work has been ongoing for nearly a year and a lot of testing has been done and a lot of changes behind the scenes, but last week the last of the old LACs were removed leaving only the new ones.
Even after all of the testing, this has led to a handful of edge cases where SIMs did not work. The main issues are around the use of usernames and passwords with SIMs.
In general these do not matter as the SIM is authenticated by its ID, but cases where end devices sent a blank username or password rather than simply not authenticating, have caused issues.
As a workaround, we have today implemented some defaults for blank username and password. This will not affect SIMs using our IP, but if we are relaying a connection to you then you may see some new authentication details. The old LACs did this too, so it should not cause problems for any customers. The default username passed on is the ICCID, and the default password is the word "password".
Obviously customers are welcome to use actual username and password authentication if you wish, but we would usually recommend authentication on the calling station ID (the ICCID).