There are many reasons this can happen:
- KDP (Amazon) have to do updates to the KDP system
- KDP (Amazon) could be updating their servers
- There could be issues happening, servers down or something else
- Your connection to them is to slow
- Browser you are using is not playing nice with their system
In 2 or 3 cases we have seen where KDP told one of our users not to use a specific browser, in the latest case, it was because they were using Microsoft Edge. He switched to Chrome and no issues
Below is the error message he got in the last case
In most of these other cases, just try again a few hours later. If you have issues you can contact KDP anytime, but I personally wait 8 hours and just work on something else.
In the case of connection to slow, check our speed test article out.