When you click the "Go to Omnivore" button in Magento, and it does not log you into Omnivore, instead it shows the Create Account screen.
This can happen for a couple of reasons, all of which are related to changes in configuration within Magento.
Please record the details from the Create Omnivore Account page, create a support ticket and we can investigate the issue.
Please copy and paste the details that appear on the screen so that we can clearly read what the information is saying. The more information you give us the easier it is for us to resolve the connection problem.
Also if you can think of any more relevant information that might help, any changes made, upgrades, attempted upgrades, new plugins etc.
This error generally points to changes that have happened within Magento, therefore more information is best.