I think that's a outdated / misconfigured SSL issue on your side; I'm seeing a valid chain: ISRG X1 -> Let's Encrypt R3 -> chemicalaid.com. Qualys SSL Labs give

I think that's a outdated / misconfigured SSL issue on your side; I'm seeing a valid chain: ISRG X1 -> Let's Encrypt R3 -> chemicalaid.com. Qualys SSL Labs gives it an A+ on both IPv4 [1] and IPv6 [2]. [1]: https://www.ssllabs.com/ssltest/analyze.html?d=www.chemicalaid.com&s=162.243.216.68 https://www.ssllabs.com/ssltest/analyze.html?d=www.chemicala... [2]: https://www.ssllabs.com/ssltest/analyze.html?d=www.chemicalaid.com&s=2604%3aa880%3a0%3a1010%3a0%3a0%3a5c%3ac001 https://www.ssllabs.com/ssltest/analyze.html?d=www.chemicala...