It’s normal.
Phone can connect to other LTE Band then your EP06 and that’s all.
You should check every Band by Band at EP06 and this way you can do proper connection.
BTW. You know that even connection will be Cat.6 with CA then your wAPR have got 100Mb port !. Be aware of that.
Check good howto at http://forum.mikrotik.com/t/quectel-ep06-e-and-wap-r-ac-rbwapgr-5hacd2hnd/131724/9 , next post have got info about change Band by AT command.