Thank you for posting to our forums!
I'm sorry to hear you are having troubles getting set up. Are you seeing any error messages? If so, please look over this article to see if any of the items apply to you: What to do about an error registering my Endicia account?
If you aren't seeing any error messages, will you please try on another browser and see if that works?
Please let me know in the comments. I'd be glad to troubleshoot further if needed.