Thank you for your post!
One thing that you will want to ensure is that the third field, the drop-down menu, is set to ‘Rithmic Paper Trading.’ If it is set to Rithmic 01, or another option, it will not go through since it is the type of account used for the demos.
One other thing to watch out for is including spaces in the username or password. A space will count as a separate character when logging in, so if you copy and paste and accidentally include a space at the end, it will not login correctly.
Let us know if either of those does the trick!