can you try nginx -T (captal T)
you site doesn't reply on https at all, openssl s_client to your site says it didn't sent anything for TLS handshake.
tcp looks open though. maybe nginx passthough tls but nothing behind that proxy?
CONNECTED(00000003)
write:errno=0
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no peer certificate available
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No client certificate CA names sent
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SSL handshake has read 0 bytes and written 303 bytes
Verification: OK
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New, (NONE), Cipher is (NONE)
Secure Renegotiation IS NOT supported
Compression: NONE
Expansion: NONE
No ALPN negotiated
Early data was not sent
Verify return code: 0 (ok)
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