TL-MR6400 4G router and B&You SIM not connecting to Internet
I have a MR6400 router. I use it whilst on vacation in France with a local French SIM for Internet access.
I have bought a B&You SIM "sans-engagement" with 300Gb data per month.
I have activated the SIM in a mobile phone and tested that it works fine.
It also works to provide a wi-fi hotspot to enble me to access the Internet from other devices.
However...
When I put the SIM in the 4G router the Internet fails to connect.
The router works with a different SIM for another French network and with the UK SIM from my mobile phone - but not with the new SIM.
I have tried everything and not yet solved this problem.
Any ideas/advice gratefully received.