Sorry for delay. In case of an answer I thought an e-Mail will sent to me.
Port forwarding to 80->887, 443->888 do not solve the problem. Than I go back to the standard 80->80, 443->443.
My synology server is not registered to synology DDNS. So, the acme client have to use the challenge type http-01.
I found the hint: “In November of 2019 we will stop allowing new account registrations through our ACMEv1 API endpoint.” End of Life Plan for ACMEv1
At my synology I changed the first line in ‘/usr/syno/etc/letsencrypt/letsencrypt.default’ from ’ “server”: “https://acme-v01.api.letsencrypt.org/directory” ’ to ’ “server”: “https://acme-v02.api.letsencrypt.org/directory” '.
Running the command on my synology
$sudo /usr/syno/sbin/syno-letsencrypt new-cert -d sub.my-domain.de -m info@my-domain.de -v
comes with the error: {“error”:204,“file”:“client_v2.cpp”,“msg”:“No Nonce… Not Yet implement”}
How can I implement the client acme-v02 on synology DS?
Are there other solutions?