An error message you may encounter when using TaxSlayer ProWeb looks like this:
This message is generally transitory and will eventually go away. That said, read "The most common reasons for this error" and "What to do now" info and follow the steps to see if it resolves for you.
If you're on a Windows PC using either Chrome or Edge, try the other browser to see if it has the same problem.
If you're on an Apple device and are using the Safari browser, try using the Chrome browser to see if that helps.