I have a new Huawei B818 modem and the password only works on my laptop. When i go to join the network and put in the password on my iphone and iPad it says the password is incorrect and won't let me join the network.
Check that the casing (uppercase/lowercase) is correct for both the SSID and password. Your phone might be auto-capitalising the first letter of one/both of them.
I do NOT have an IOS device. Check you are using a compatible security mode between the B818 and the IOS version you are using. I suggest forgetting the network and setting the WIFI up again. Try it with a simple password with alphabet and digits only first up and it it works then change the password to a stronger password.
On Android I am using "WPA/WPA2-PSK" and do NOT have hide Wi-Fi ticked. I also have the Bandwidth and channel on auto.