If the URL you are using has an ID at the end of it, then you need to update it to your custom URL.
For Example: https://www.coloradogives.org/index.php?section=organizations&action=newDonationStandard&fwID=12345
How to find my custom URL?
When you log into your organizational profile, click on Settings and then General Settings. Here you will find your custom URL that you can place on your website to direct donors to your organizational landing page on ColoradoGives.org