It seems that you are using sudo, please read this link first:
https://github.com/acmesh-official/acme.sh/wiki/sudo
If remove the "sudo", CLI shows error:
...
2020/05/09 21:03:28 socat[2038] E bind(5, {AF=2 0.0.0.0:80}, 16): Permission denied
[Sat May 9 21:03:33 HKT 2020] mydomain.me:Verify error:Invalid response from http://mydomain.me/.well-known/acme-challenge/seMUrEsUr47-Lc9Nc7cS3xQO8VmhVMjfXhw0wcGEmIc [64.32.28.244]:
/home/naidaomeihui/.acme.sh/acme.sh: line 2271: kill: (2038) - No such process
[Sat May 9 21:03:33 HKT 2020] Please add '--debug' or '--log' to check more details.
[Sat May 9 21:03:33 HKT 2020] See: https://github.com/acmesh-official/acme.sh/wiki/How-to-debug-acme.sh
...
Under Ubuntu 18.04, if use this command directly:
CLI shows:
If remove the "sudo", CLI shows error:
Finally, according to [https://github.com/acmesh-official/acme.sh/wiki/sudo], add --force at the end:
Succeed.