reCAPTCHA score (0.00) on CF7

We’ve been using CF7 with reCaptcha v3 for several years without trouble, then the form suddenly stopped sending messages because they’re all being flagged as spam.

When we installed the Flamingo plugin we noticed that all messages, both legitimate and spam, had “Spam log: reCAPTCHA score (0.00) is lower than the threshold (0.50).” in the status.

We tried installing newly generated reCaptcha v3 keys (suggested in another thread) and clearing all caches but that hasn’t solved the issue.

We’ve had to remove the CF7 form from our website for now, so we don’t annoy users. But long-term we’d like to sole the issue.

Any ideas why ALL messages submitted via the form have reCAPTCHA score (0.00)?