Is it possible you are entering it incorrectly? Maybe you got a “sticky” key. Try copying the password from the admin panel & pasting it in directly.
Also make sure to turn off “Private address” in the Wi-Fi options on iOS. It has caused some issues in the past for me.
If it still doesn’t work, you could try the beta firmware. I don’t know if this issue was reported before, or a known issue, but it’s possible it got a (silent) fix.
You can download beta’s from here, mind you they might be unstable.
Unfortunately none of these worked. I double checked the key. My iPhone doesn’t have a private wi-fi address (OS is new, but the phone is old, an iPhone 7p). Even tried the beta firmware. No dice.
Seems some folks in this reddit have a similar issue (further down the page):
I’ve discovered the hot spot issue, then wi fi dropping, and now I’m seeing that my VPN speeds (when I can keep wi fi up) are down to like 20% of my connection speed (the app version of this same VPN provider are at about 80%).
This is on different wi fi networks even using different laptops.
Seems like way too many problems for a device that is supposedly so popular.