Form error using PHP 7.4

Are there known issues with php 7.4

No.

Then why am I not able to send any forms? Could you test the form on the contact page of the website I sent? I have more examples.

FAQ > After submitting the form, I get an error message stating “There was an error trying to send your message.” What is wrong?

I wonder if that is true. This is the error I’m getting using PHP 7.4:

{"into":"#wpcf7-f824-p16-o1","status":"mail_failed","message":"Failed to send your message. Please try later or contact the administrator by another method."}

Same server using PHP 7.3, no problems.

FAQ > I get an error message with a red border. So, how can I solve this?

It’s not CF7 that has problems, but apparently there is a problem with PHP 7.4.1 and wp_mail() which CF7 uses. This should be solved with PHP 7.4.2.

I didn’t have any luck with PHP 7.4.2 (bad build I assume) but all is well using PHP 7.4.5 with the latest version of WordPress 5.4.1 on three different websites all using different themes. Clearly not a Contact 7 problem.