DuckDns add-on won't start anymore

Hi,

Without changing anything my duckDns add-on stopped and won’t start anymore. I’m only able to reach my web interface in stealth mode by skipping the invalid certificate warning.

I expected the add-on would renew the certificate automatically but it seems like that has not happened.
The log file on the add-on page is empty.

Can anyone point me in the right direction?