Red error on form submission

I’ve recently noticed that my contact form has stopped working on my site. I initially thought that this may be due to using WP-cerber and its anti-spam although after seeing this article: https://contactform7.com/faq/after-submitting-the-form-i-get-an-error-message/ I noticed that the error is read and therefore not a spam issue.

I then thought that this may be due to my WP Mail SMTP plugin but after playing with the settings the issue still persists.

Is there anything else that I can try in order to get my contact form working again?

Many thanks,
James

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