invalid multibyte sequence…. Textarea escapes…

I noticed some errors from the contact form page on my website..

Initially I was getting:
mod_fcgid: stderr: PHP Warning: htmlspecialchars(): Invalid multibyte sequence in argument in*****gloucesterphotographer/wp-includes/formatting.php on line 3192, referer: http://www.gloucesterphotographer.com/contact-me/

I changed the date dropdown box to a plain text field, the error has now moved to..

mod_fcgid: stderr: PHP Warning: htmlspecialchars(): Invalid multibyte sequence in argument in*****gloucesterphotographer/wp-includes/formatting.php on line 3205, referer: http://www.gloucesterphotographer.com/contact-me/

line 3192 is this bit..

function esc_textarea( $text ) {
$safe_text = htmlspecialchars( $text, ENT_QUOTES, get_option( ‘blog_charset’ ) );
/**
* Filter a string cleaned and escaped for output in a textarea element.
*
* @since 3.1.0
*
* @param string $safe_text The text after it has been escaped.
* @param string $text The text prior to being escaped.
*/
return apply_filters( ‘esc_textarea’, $safe_text, $text );
}

Sorry for rambling… I can’t figure it out but my contact page is pretty simple if it helps get to the bottom of it.

All best
SI

http://www.gloucesterphotographer.com

https://ww.wp.xz.cn/plugins/si-contact-form/