I have checked as best I can the DNS, Port forwarding (Ports 80 and 443) I can renew my Synology certificate without problem but your certificate renewal fails.
Please fill out the fields below so we can help you better. Note: you must provide your domain name to get help. Domain names for issued certificates are all made public in Certificate Transparency logs (e.g. crt.sh | example.com), so withholding your domain name here does not increase secrecy, but only makes it harder for us to provide help.
My domain is: Ravensbourne.dyndns-web.com
I ran this command: I selected "renew" on my Synology NAS
It produced this output:" Please check if your IP address, reverse proxy rules and firewall settings are correct and try again
My web server is (include version): Synology DS220+
The operating system my web server runs on is (include version):DSM 7.01-42188
My hosting provider, if applicable, is:
I can login to a root shell on my machine (yes or no, or I don't know): don't know
I'm using a control panel to manage my site (no, or provide the name and version of the control panel):
The version of my client is (e.g. output of certbot --version or certbot-auto --version if you're using Certbot):