daniel@optepr0n:~$ openssl s_client -servername masto.rootdc.xyz -connect masto.rootdc.xyz:443 | openssl x509 -noout -dates
depth=2 O = Digital Signature Trust Co., CN = DST Root CA X3
verify return:1
depth=1 C = US, O = Let's Encrypt, CN = Let's Encrypt Authority X3
verify return:1
depth=0 CN = masto.rootdc.xyz
verify error:num=10:certificate has expired
notAfter=Jan 17 01:08:56 2020 GMT
verify return:1
depth=0 CN = masto.rootdc.xyz
notAfter=Jan 17 01:08:56 2020 GMT
verify return:1
notBefore=Oct 19 01:08:56 2019 GMT
notAfter=Jan 17 01:08:56 2020 GMT
DONE