How long has it been since you last logged in? I thought the Gateway was shut down two years ago.
The camera might be brand new, but the model is a few years old. Follow the instructions at the link and be sure to download the latest copy of the User Manual.
When you first set up the image.canon connection through the EOS Utility it will have an Image Gateway login prompt. Once the connection is established it will be done through the current image.canon cloud service.
There are a few things to check when the login isn't completing. The first is to make sure you have the current version of the EOS Utility installed. The current version can be downloaded HERE. Once you are on the web page click on the gray Drivers and Downloads button and the current version is EOS Utility 3.15.0. Once the EOS Utility is updated check to see if the same thing is happening.
If the issue continues the next thing to double check is that you have an account set up HERE. If you do not currently have an account on that page click on the gray person icon and you will have the option to create an account. Sometimes if you do not have a Canon account set up there it can prevent the log in from going through.
If that doesn't resolve the issue then we would recommend installing EOS Utility on a different computer and try to set up the connection there. Sometimes operating system or security software settings can cause issues like this. If the log in goes through on a second computer that indicates settings on the first computer were causing the issue. In that case we would recommend contacting the maker of your operating system and security software to trouble shoot their settings.
I'm having the same problem with my rebel T6 (1300D), I've tried:
Different computers, different operating systems, setting up firewall exception, different networks, different versions of EOS utility, contacted the Canon service center to check there was something wrong with my account setup.
Still can't find a solution