Mobile Data stopped working I have a Nokia Sirocco 8.1 mobile phone, about 2 weeks ago now my mobile data turned off or stopped working, I contacted my carrier (Boost mobile who use the Telstra network in Australia) they went through all resetting data and checked my SIM activity, all good their end but phone still does not CONNECT. 

I contacted Nokia support and they also went through all resetting options and suggestions, I even purchased a new SIM and tried it, still no connection, last thing was a full factory reset of my phone, but still no data connection, all other functions work on the phone, calls, text, wifi all PERFECT. 

I have Youtubed for answers as well, tried everything all suggestions but still no Data: is there an inbuilt antenna that picks up data signal or is it a circuit board issue that needs replacing or do I just have a dud phone? 

I have to say I have had the phone for over a year and have had no issues, I have used 650 Mbs of a 30Gb plan so I have plenty of Data available, please help me I am very frustrated at the moment.
I had Data roaming issues with my Nokia 8.1 Sirocco phone, tried all avenues for answers, Telstra support, Nokia support, all resets and even tried a full factory reset but all efforts did not work. 

I sent my phone to Nokia in Sydney, they called me and told me phone was working there, I had to reset my APN protocol and APN roaming protocol. 

From settings &rarr; network &amp; internet mobile networks &rarr; advanced  &rarr; access point names and changed settings from IPv4 to IPv4 / IPv6, pressed the 3 dots top right hand corner and pressed save. 

It works  now again, hope this helps anyone with same issues.