Static using external mic on iPhone Xr

Recently purchased a Rode VideoMic Go with SC7 cable to work with iPhone Xr I use an official Apple Fire to headphone jack.

The issue is that when recording there is static clearly over the audio; a tick tick tick... it improves marginally when I remove the wind muff but frustrated that sound is not clear. I have had the mic checked out by Rode and they assure me the mic is working perfectly. I've tested it out of phone case, different locations, different cables but only the Rode SC7 works, no neon lights or electric motors nearby...record without external its okay. I want to use the Rode GO shotgun feature at times.

Anyone else suffered similar problem and have any suggestions?