Hello,
So originally we had an issue where sometimes, when trying to connect to our iPhones to our FiOS router, it would say "Unable to connect" when the password was 100% accurate. 2 of us with the same phone and updates would do it, it would work for 1 person and take about 5-10 tries for the second person to get on. It was only an iPhone issue at first, and I had read about some issues with them internally that may have been causing this.
However, today, my wife tried connecting her Lenovo work laptop to the router. It had previously been connected but somehow lost the connection. She entered the password and got the "Unable to connect" message. She verified the password was correct and tried 5 times to no avail. It finally worked the 6th time doing the same exact thing.
Is there any tech reasons this could be possible or figure out a reason for why this is happening and how to prevent it in the future?