Possible reason: your host may have disabled the mail() function…

And what is the question?

Solution found:

The last comment someone made on a post corrupted the comments table in the database.

All I had to do was delete the last comment from the table & viola.

https://ebestagent.com/wordpress-your-host-may-have-disabled-the-mail-function-error/

I am having the same issue and the site you linked to suggests that is has something to do with the plug in Comment Relish.

Does anyone else with this problem have that plug in installed? I do…

I just had the problem solved, all you need to do is just remove the wp_cr_email data base and then login to wp-admin to deactivate the comment relish plugin.