How can I get my mobile network working on my LG Optimus G E975 after flashing CyanogenMod 12?

[AC Question]

CyanogenMod 12 on lg optimus g e975

CyanogenMod 12 on lg optimus g e975
Hello All
PLEASE HELP I AM NEW IN THIS FIELD AND KNOW NOTHING
AFTER FLASHING cm-12-20150414-NIGHTLY-e975, GAPPS gapps-lp-20150222-signed AND UPDATE-SuperSU-v2.16 ON MY CONVERTED LG F180s TO LG Optimus G E975
My Mobile Network IS NOT WORKING, NETWORK SIGNAL IS MISSING and not make ANY call AND WHEN I CALL A NUMBER ERROR MESSAGE
ERROR:- "TO PLACE A CALL, FIRST TURN OFF AEROPLANE MODE " WHILE AEROPLANE MOD IS OFF IN MY PHONE SETTING
how can I repair it