FWIW, there’s a hex block that follows the error, and it does contain the url provided above, as well as a bit of non-ascii hex and the following statement:
“This Certificate may only be relied upon by Relying Parties and only in accordance with the Certificate Policy found at https://letsencrypt.org/repository/”
This is different than what I see for 184.108.40.206 when I print out chain.pem:
0000: 16 22 68 74 74 70 3A 2F 2F 63 70 73 2E 72 6F 6F ."http://cps.roo
0010: 74 2D 78 31 2E 6C 65 74 73 65 6E 63 72 79 70 74 t-x1.letsencrypt
0020: 2E 6F 72 67 .org
This tells me that I’m able to parse a 220.127.116.11 object in at least some form.
Since this implies that there was something different (and maybe malformed) about my cert, I went ahead and regenerated it (just in case I had somehow corrupted it), but the new certs show exactly the same thing.
At this point I have no idea how to continue troubleshooting this issue. What are other steps I can take?