That alert is indicating there is high Radio Frequency (RF) interference on your network. These guides reviews how troubleshoot for RF interference, depending on which HiveManager platform you are using:
HiveManager Classic: https://thehivecommunity.aerohive.com/s/article/Radio-Frequency-Interference-Troubleshooting
HiveManager NG: https://thehivecommunity.aerohive.com/s/article/Radio-Frequency-Interference-NG
If you can send me tech data from an AP that is having these issues, I can take a look at let you know what we see as far as interference levels go, and what we can do to mitigate the interference. Below are some guides reviewing how to get tech data, again depending on which HiveManager platform you are using. If you could email the data to me at communityhelp@aerohive.com, I would appreciate it.
HiveManager Classic-https://thehivecommunity.aerohive.com/s/article/How-to-download-tech-data-in-Classic
HiveManager NG-https://thehivecommunity.aerohive.com/s/article/How-to-download-tech-data-in-HiveManager
Device CLI-https://thehivecommunity.aerohive.com/s/article/Collecting-Tech-Data-via-CLI
