Well, did the following:
- Manually added an entry to the collection on server side. No joy.
- Added a valid (as per http://icalvalid.cloudapp.net/) .ics event via cadaver. No joy.
- Tried adding my existing account once again (already in DAVdroid, working since 6.3, i.e. half a year or so, successfully). No joy.
I know radicale has to have data before you can use it. This was the same with my working account back then (and this should be part of the docs, as it really took me long to find this out.)
Is there an apk archive (plus nightlies so I can test your referenced fix)? I think this would greatly help to rule out one end or the other!