as i mentioned earlier, one reason for this could be that the s/n entered does not match that of your rc. that was my problem. i sent an email to support and they answered this within a day. not sure how they figured out that my s/n was wrong since i didn't include this in the support email. i was unable to read it off the tag on the rc but got it correct s/n from the dji go 4 app. earlier post told how to do this but i think it was under general settings / about and scroll down. don't have the app with me to verify
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