We are having a problem with devices connecting to Ubiquiti AP's. The problem seems to center around Apple devices connecting, re-connecting, and staying connected. Example of one of the quirks: Existing iphone that has been on (knows) the network will still ask for the password and then reject it. And maybe after rebooting the iphone/ipad, it'll catch and connect after 10-20 mins. PC's, android devices, etc connect and stay connected just fine. We are having this on several recent projects so we believe it's something we're doing/not doing.

We install a cloudkey on every project so it may be possible for us to adjust remotely.

Unfortunately, that's just Apple products in general. Make sure fast roaming is off.
Also, another thing you can try is to change the DTIM mode under the wireless network to either 2 or 3.

Turn of WiFi on the iPhone, then turn it on again. It's a PITA, but it helps. If you need WiFi to make calls, that sucks.

Apple devices hang on for dear life, almost like a baby's separation anxiety when mom tries to hand it off to someone else.

I have a bunch of Ubiquiti/Apple customers and I'm not receiving complaints. On set-up I explain the roaming issue (several times) and how to work around it.

I too have many sites with multiple APs and all of them have Apple phones, tablets and MacBooks and have zero issues.

Which APs are you using? I have not had good luck with LRs; mostly stick to AC Pro, AC M, Nanp HD and the newer FlexHD

Tuning wifi channels/power settings with an analyzer? Fast roaming should be off by default and channel spacing set to HT20 for 2.4 and VHT40 for 5 (also defaults)

I have one client that has been a total PITA, in part because he doesn't know what he is talking about but was making demands (such as demanding 5GHz speeds everywhere and wanted us to shut off 2.4GHz.  That created a host of issues.  He is all Apple and experiencing poor roaming.  We tried all the suggestions here, but his issues continue.  I have an Android and can walk around his house and outside and the phone jumps fine.  I instructed him before we every installed the network that he will likely have to turn wifi off and back on to roam, as Apple latches on.  He would not listen to reason and I was ready to swap the entire thing out for Eero when he talked to his IT guy at work, who I happen to know.  The IT guy basically confirmed everything I was telling him, which eased him, until several weeks ago, when he asked me for his cloud key login.

We exclusively use the AC Pro's. On friday, our distributor gave us a number of a dealer in another city that uses tons of Ubiquiti. I called him and he had plenty to say about our situation and described the problem with Ubi + Apple. He told us a solution and we were able to implement it remotely. He suggested we separate the 2.4 and the 5 bands. For testing we named the 5g "apple network" and the 2.4 "aux network" (we'll come up with a better naming scheme later). Sure enough this solved the problem at a site where idevices were letting go, not connecting, etc. He also stated this is an issue with newer apple devices which does seem to be the case here.

This is completely counter to our SoP concerning wifi setups. As old engenius dealers, we were taught to 1) combine the names. 2) knock 2.4 to 20hz only + 5 to 40hz only. 3) use aes encryption. We have ~300 of those AP's in the air over the last 6 years with zero issues.

Good stuff, I will keep an eye out for this behavior in the field. I'm sure my clients all have the latest of Apple anything.