Email Links Showing as Invalid (but they're not)

I've included a photo below so you can visually see what I'm referring to.

When I try to get a line of text or button to link to an email address with another email copied, it's saying the email is invalid.

It will only let me use one simple email address.

I've added a copied email on practically all of my emails sent out through Constant Contact in the past. I've even double-checked the article in the Knowledge Base for any potential changes after the most recent update, but there were none.

Not sure why this has become an issue now when it always worked previously.

I hid the emails in the picture for privacy concerns, but they are spelled correctly, no mistakes there.

Any advice on how to fix this?