Spam error because a word

Hello!

I have a contact form that sometimes fails sending emails, because it thorught the orange error.

The strange thing is that the contact form is failing when I put de word “Moya” (a typical spanish surname).

I tried the following and still fails:
* reinstall the plugin
* install and configure the plugin “Easy WP SMTP” to see if there is a problem seding mails
* deactivate the theme, activate the “Twenty Seventeen” theme and try sending

The only thing that makes the form works is to delete all the words in the blacklist (which was the default list, no personalized).

Any adviced?

Thanks in advance

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