If you are re-uploading a COI and the Submit button still hasn't turned blue, it's important to look at a few items:
1. Make sure the COI you uploaded is active and not expired.
2. Scroll down to the bottom of the page. Make sure all the check boxes for the policies covered on your COI are checked and that the expiration dates are correct and active. 
3. Make sure you've read and made the necessary changes your GC may have sent you after rejecting one or more policies. 
4. You can also take a look at the top of the page. Usually the error that is preventing you from submitting a COI will be appear there in red text.
