If you get the following error on your website:
ERROR for site owner: Invalid key type
It’s probably a Google ReCaptcha error, which is probably caused by code for Google ReCaptcha v2 using a Google ReCaptcha v3 key.
To fix this, either use the correct Google ReCaptcha code for the version of the keys you are using, or use the correct version of the keys (which you can get from the Google ReCaptcha website) for the code you are using.