Oppo Can't connect to three WiFi underground

[Manuelsilvaa731]

So I just got a new device which is the OPPO find X5 pro and connected the SIM card in the tray and everything was working perfect underground, I'd connect to the WiFi and after a couple confirmations it would sign me in through the SIM cards credentials, recently i changed from a physical SIM to a E-SIM, now I've tried every single combination of settings i can try but to no luck it just keeps coming up with authorisation failed 

[PeteG]

Hey there.

Welcome to the Three Community. 

I've seen this issue pop up ever now and then in the past, but haven't seen it recently. It seemed to be Oppo and OnePlus users that were most often affected. As far as I could tell, it seemed to be a software issue, as there was a few users on other platforms that confirmed that when they put their SIM back into their old phone, it connected normally. 

You might find success on this post here. User cgreenhalgh mentions about 3 quarters of the way down the page that he managed to get it working after fiddling with the settings. Might be worth giving that a go?

Pete.