Got issue with the App connection to my peephole wifi

[Sabababb]

bought the peephole few month ago sync perfect to my Wi-Fi 2.4 --few week ago i got error " FAIL TO CONNECT TO THE NETWORK "
i didn't change anything no setting nothing = so IGUESS router isn't the issue but the App maybe update ?? (got the latest ver 3.35.5

btw -- its connect via hotspot perfectly

Thanks