Multiple HTTPS entry points with ACME LetsEncrypt DNS in Traefik

I have successfully configured ACME / LetsEncrypt to use DNS challenge, but I'm still unable to create multiple HTTPS / TLS entry points on different ports (443 and 8443) using guidance from this post.

Error creating TLS config: No certificates found for TLS entrypoint https8443

Here is the relevant section of my config:

defaultEntryPoints = ["http", "https443"]

[entryPoints]

  [entryPoints.http]
  address = ":80"
    [entryPoints.http.redirect]
    entryPoint = "https443"

  [entryPoints.https443]
  address = ":443"
    [entryPoints.https443.tls]

  [entryPoints.https8443]
  address = ":8443"
    [entryPoints.https8443.tls]

[acme]
email = "user@example.com"
storage = "/path/to/acme.json"
onHostRule = true
dnsProvider = "cloudflare"
#delayDontCheckDNS = 0
entryPoint = "https443"

[[acme.domains]]
  main = "example.com"
  sans = ["a.example.com", "b.example.com"]