Invalid SSL-certificate

Hello

I am running https://radio.horsens-garage.rocks:8443. The SSL-
certificate is made like this:

cat /etc/letsencrypt/live/horsens-garage.rocks/fullchain.pem
/etc/letsencrypt/live/horsens-garage.rocks/privkey.pem >
/etc/icecast2/bundle.pem 

I have had no errors or warnings in any browser. Until now! Fulguris, a
FOSS-browser for android, gave me a warning about invalide date in the
certificate...

https://horsens-garage.rocks has a mediaplayer, that will stream music
from the radio. If I test horsens-garage.rocks in a "Test-Your-SSL"
site, there are no problems. But if I test radio.horsens-
garage.rocks:8443, it report invalide date.

https://www.sslshopper.com/ssl-checker.html#hostname=radio.horsens-garage.rocks:8443

But they both use the very same letsencrypt certificate! Icecast use
the bundle.pem made from the letsencrypt certificate/key.

<ssl-certificate>/etc/icecast2/bundle.pem</ssl-certificate>

Does any of you know what is wrong?

-- 
Thomas Jensen, Denmark