First of all. Thank you for getting back to me.
On my iPhone 8 plus the internal (factory) mic is working. Also, when I plug in the stock headset (the white one) that come with the phone works great. (The ones you use to make phone calls and listen to music. They work great. )
This is where I'm having the issue:
I'm plugging in the phone adapter for the round plug. 4 to 3 pin adapter. I have several systems like the "Rode" wireless mic also "Rode" plug in mic. The "Zoom" systems and a few others. ALL which worked great in the past. But not now.
Just a couple of hours ago I restored the iPhone 8 plus. NADA.
I ordered new cables and NADA didn't work.
Here's something I even tried.
I plug in the stock white headset (factory come with the phone) and I scratch the bottom speaker on the phone and the scratching sounds do not show up in the recording. ; ) and the white headset picks up the audio on the recorder and video fine.
MAYBE this helps give some clues. When I plug in the external Rode and start recording and even videoing and scratch the bottom of the phone the sound is picked up on the phone mic.
So, the external mic is not working. The phone is not connecting with the external mic.
I hope any of this helps and your help is really appreciated.
Thank you
Derek Wolf