Hello,
Please post a log with topic=lte .
I recommend to use ros6.47.4 or newer and the lte module firmware should be 026.
I solve for some users with MikroTik support some similar problems and support have a new beta.. but first public your logs.
You can track changes at cells etc by LTE Logger: http://forum.mikrotik.com/t/r11e-lte6-2ca-not-staying-connected/136004/22
What CME ERROR you have, give log.
23430 is not a cme error but ID of ISP EE in UK, base at CellMapper information.