Hi - My dongle is attached to AC750... it's SIM is inserted and is online - the TP Link router is switched over to 3G/4G and is configured with all the APN and ISP stuff, pretty sure it's right... just need the router to recongnise the th Huawei E3372 dongle. Do you have a driver? - It's coming up as 'identifying / disconnected' presently. 

The model no above doesn't include the the AC750 - even though you make it... and this is your website!