Project failed, boss says I didn’t flag it in time, but I literally emailed it early on

A project I was working on just went south. During execution, I noticed a few key milestones starting to slip. To make sure I wasn’t misreading the data, I even used acciowork and chatgpt to dig into it. Once I confirmed the risks, I wrote a pretty detailed email to my boss laying out the red flags, potential impact, and what I thought we needed to do ASAP.

Sent the email, No response, Over the next few weeks, the project kept moving, but the core issues were never really addressed. Eventually, the whole thing failed.

In the postmortem, my boss straight up said: "Why didn't you flag this earlier?" I told him I did. I pulled up the email afterwards, timestamp, recipients, everything clean. I even explicitly called out the risk of the project failing.

He didn’t deny the email existed. But his response was basically “If it was really that serious, you should’ve made sure I saw it.”

Now most of the blame is still landing on me, and I’m kinda stuck on this, am I actually in the wrong here?