Form not working after upgrade

Since upgrading to Contactform7 5.1.1, my contact form is no longer working. I get this error when submitting:

Failed to send your message. Please try later or contact the administrator by another method.

Additionally, recaptcha v2 stopped appearing. I upgraded to v3 and installed the new keys. I also removed the recaptcha form tag as instructed by Contactform7. The recaptcha still does not appear.

Any idea what the issue is?