ejabberd ACME unexpected content type when it receives certificate - ejabberd

Question

I am running a processone/ejabberd container that i am trying to get to request a certificate via ACME to a smallstep ca container. The request fails with this error:
#{<<"kid">> =>
<<"https://ca.mydomain.local:8000/acme/acme/account/svUkT7QwXD4pBqyrVdys94VMeVCeeo0D">>,
<<"nonce">> =>
<<"..">>,
<<"url">> =>
<<"https://ca.mydomain.local:8000/acme/acme/certificate/Jks2zJjdJwqDzE7VSsLM0TOaAzzYUB2P">>}}
2022-11-07 08:30:28.355858+00:00 [debug] HTTP request: {post,{"https://ca.mydomain.local:8000/acme/acme/certificate/Jks2zJjdJwqDzE7VSsLM0TOaAzzYUB2P",
[],"application/jose+json",
<<"{\"signature\":\"....\",\"protected\":\"......\",\"payload\":\"\"}">>}}
2022-11-07 08:30:28.608072+00:00 [debug] HTTP response: {{"HTTP/1.1",200,"OK"},
[{"cache-control","no-store"},
{"date","Mon, 07 Nov 2022 08:30:28 GMT"},
{"content-length","2108"},
{"content-type",
"application/pem-certificate-chain; charset=utf-8"},
{"link",
"<https://ca.mydomain.local:8000/acme/acme/directory>;rel=\"index\""},
{"replay-nonce",
".."}],
<<"-----BEGIN CERTIFICATE-----........\n-----END CERTIFICATE-----\n-----BEGIN CERTIFICATE-----........\n-----END CERTIFICATE-----\n">>}
2022-11-07 08:30:28.609162+00:00 [error] Failed to request certificate for jabber-gw.mydomain.me: HTTP error: unexpected content type: application/pem-certificate-chain; charset=utf-8
2022-11-07 08:30:28.609456+00:00 [debug] Unregistering ACME challenge #Ref<0.1802325958.1657798659.124306>
2022-11-07 08:35:26.914567+00:00 [debug] Error when retrieving http headers gen_tcp: timeout
Any ideas on why its not happy with the content type and how to resolve?
Prior to the error message, the logs show what looks like a successful ACME challenge:
[<<".well-known">>,<<"acme-challenge">>,
<<"3rNIelLxSuDU0tWZgb3yEw5sL6d6Z61J">>] matches [<<".well-known">>,
<<"acme-challenge">>]
2022-11-04 04:28:12.436337+00:00 [debug] Received ACME challenge request for token: blah
2022-11-04 04:28:12.546710+00:00 [debug] HTTP response: {{"HTTP/1.1",200,"OK"},
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