API key is not valid

For the last couple days I’ve been getting the following message on my site’s dashboard:

Security by CleanTalk: API key is not valid. Enter into plugin settings to get API key.
Why do you need an API key? Please, learn more here.

Yesterday, I was just able to copy the API key from my CleanTalk dashboard and that resolved it, but today that isn’t working.

My site is protected and is supposed to be valid until September 6, 2019.

The page I need help with: [log in to see the link]