Since yesterday, it seems that the SSL certificate of svn.roundcube.net is invalid:
Certificate information:
- Hostname: MX
- Valid: from Thu, 19 Jun 2008 04:57:06 GMT until Fri, 19 Jun 2009 04:57:06 GMT
- Issuer: MX, MX, St. Louis, Missouri, US
- Fingerprint: 05:5d:aa:18:4b:25:ca:d2:96:61:2e:9d:1b:8b:34:6f:74:7c:cb:40
Looks like it was just renewed on the 19th so I would say you need to accept the new certificate and you should be good to go.
But it was renewed not using a valid hostname...
Hostname: MX
=> it should be svn.roundcube.net