Fix error while add_txt_record.

[huww98]

I got error when trying to obtain certification.

Unexpected error determining zone identifier for cn: Domain name invalid, please input tld domain

I have fixed this

[tengattack]

But if we try to obtain certification for sub domain like foo.bar.example.com, will it work?

[huww98]

I think it will work.

https://github.com/certbot/certbot/blob/v0.26.1/certbot/plugins/dns_common.py#L326-L327

It will try every possible domain.

[tengattack]

Are you trying to obtain certification for top-level domain like foo.cn?

[huww98]

Yes

[tengattack]

OK thank you!

[huww98]

I have just tested that it does not work for something like foo.bar.example.com, I will trying to figure out why.

[tengattack]

Maybe we should determine whether the domain is top-level domain or not

[huww98]

Fixed that. I have successfully obtained a certification for foo.bar.<mydomain>.con

[tengattack]

Great works!