Synology NAS, request certificate doesnt work

Hi there,

I have created a subdomain to my Synology NAS and this works:

Also i forwarded port 80 to my NAS, tested it with: telnet 80

I get connected, so the port is open.

But when i request a certificate in the Synology software (DSM 7.1) i get after a few minutes of waiting an error, to check IP, reverse proxy etc.

But when i request a certificate for the subdomain of synology,, it works!

So i'm wondering, is there some additional settings/records i need to add in Direct Admin from my domain ?

With kind regards,

Buck Baggen

Hi @buckbaggen, and welcome to the LE community forum :slight_smile:

The two names don't return identical IP information:

Addresses: 2a06:2ec0:1::135


The problem is likely in the IPv6 path.
LE will prefer IPv6 over IPv4 when present.
Ensure the IPv6 path is working OR remove the AAAA address from DNS.


Hi there,

Thanks for the quick reply!

That explains a lot!

I removed the ipv6 records from my subdomain. Now wait a bit for the DNS servers to sync and then try again :slight_smile:

I post the results here.


It works now! Thanks a lot!


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