I’ve been getting ads like these for years on my ubuntu server.
<span style="color:#323232;">n additional security updates can be applied with ESM Apps.
</span><span style="color:#323232;">Learn more about enabling ESM Apps service at https://ubuntu.com/esm
</span>
This is on a machine running 20.04. Never bothered me. All my other machines are Debian now, and at some point I’ll switch that one too.