I had someone get a very similar email trying to get someone to change a link from me to a competitor. It sounds almost identical with a different domain. They linked to some accessibility checker. The problem, the site they tried to convince didn't pass this checker either. But the person who emailed wasn't concerned about that, they just wanted a link to me changed to my competitor (who was obviously their client).

If it's the same pattern, it's just a malicious negative SEO campaign. I'm planning on writing about it soon.