Hi Rob, we answered your email but for anyone else encountering this issue, here's what we wrote:
We haven't seen this error message before but we can confirm that the CryptPad account that the PoP Bundle Team is using is certainly still active. If you use a few extensions on Firefox, check this official FAQ for things that may not play well with the site: https://docs.cryptpad.org/en/FAQ.html
If the issue persists, please let us know and we can send you the questions and input your answers for you.