After spending 2 week on this Issue I found the real problem for this
(Negotiation time out, Try again) Fail to pair message
OK I followed all the instructions from the manual
1-Flashed the GCS first
2-Connect WiFi on GCS
3-Register your GCS with your (own Number)
4-Search on the Android setting, about, and search
for the latest update (Connected to the WiFi)
5-Flash your Air Unit with the same Flash file used
to flash the GCS.
6-"This is the part that is not showed on @MadRC firmware flashing video. this simple step is super important and was the problem!
! IN ORDER TO PAIR YOUR AIR UNIT WITH YOUR GCS YOU NEED TO TURN OFF YOUR WIFI CONNECTION FIRST!
7-Pair your Air Unit without any issue!!!
And that was the problem, after spend two weeks reflashing the GCS, the Air Unit that was the problem, I was thinking today about signal issue, turned off the WIFI and BOOM, pair without any issue in less than 10 seconds.
@Michael_Oborne I really appreciate your time trying to help with information, I didn’t did the Factory Reset, I just test this and resolve all the issue.
Maybe is important to check that and update the firmware update manual because there is a lot of persons asking for the same issue and maybe this will help the entire community.
Also thanks @Jai for trying to help.