'This field has syntax errors.' in Additional Headers for Reply-to

Hello

I’m trying to resolve a configuration error on two of my three forms. All three of them have a Reply-to within the Additional Headers, but only two of them give me the ‘This field has syntax errors.’ error.

Here’s the format of the ones giving error;
Reply-to: [FirstName] [LastName] <[EmailAddress]>

And this is the format of the working one;
Reply-to: [your-name] <[your-email]>

The only difference is the field shortcodes used. The first two have different fields being used hence the different shortcodes, they’re valid shortcodes though as it’s the correct field naming.

Any help appreciated,
Cheers

https://wordpress.org/plugins/contact-form-7/