I think this is the same issue than the one reported here:
https://forum.sailfishos.org/t/kolab-now-and-sfos-3-4
I give a workaround there, maybe you can try it if you’re stuck without calendar… Besides, as said on the other thread, I’ll discuss this with @chris.adams next Tuesday on IRC channel #sailfishos. Lets see then what solution can come out.