Hmm, that should work ok. Silly question time, are you sure you are connecting to the WAN port (LAN port 4)
Yes definitely, could it be something with the BT modem, how do I access it to check?
It's not a problem with the BT modem as just connected an old tplink td-w9980 and set up in wireless router mode and that's connected fine. So I must be missing something on the new router I'm trying to setup
Might be worth checking if there is a later version of firmware than you have. Ensure connection type is PPPoE and not PPPoA
It is PPPoE and it looks to be the latest version of firmware. Might have to try tplink forums
Yes, sorry, can't think of anything else it might be. Bit of a long shot, wonder if it will only work if the 4G sim is fitted for backup despite being set to wireless router mode.
I'm trying to have a look at the settings on the TP Link emulator site https://emulator.tp-link.com/mr600-v1-en/index.htm, but unfortunately it doesn't seem to work when you change to wireless router mode.
You could try changing its IP address to 192.168.1.254 rather than the default 192.168.1.1 as the HG612 modem uses 192.168.1.1 as its default management address but as the 9980 worked ok and that uses 192.168.1.1 I'm not sure if it will help but anything is worth a try.
If authentication is set to auto, try setting it to CHAP