Please be kind if the post is not placed in the right location. My home gateway / vivid wireless "4G" account is a few years old, but it seems that the speed is getting slow more often, which is quite frustrating. Looking on the forum, it is recommended to have a look at RSSI and CINR parameters, so I tried to logon to 192.168.I.I as recommended, but got a fail -1 error when entering logon details. Can you please help?

First, you need to establish that is actually the IP of your router. Open a command prompt on your computer (if running Windows) and type IPCONFIG, then hit the enter key. Look at the default gateway IP address. This is going to be the IP of your router.

I assume it is because you mentioned that you get an error logging in which indicates that you are getting to the login page. If you dont have the login credentials, you should be able to reset the router to defaults (there should be a button somewhere on the router) and if you look at their documentation, the default userid and password should be there.