[horde] Problem with authenticating for calendar by "Subscription URL"

[Wojtek]

You're right, I did it again. The thing is I didn't even try to use 
Thunderbird, I tried to get directly to the calendar through:
http://serv.addr/horde/rpc.php/kronolith/user@srv/user@srv.ics

There is a popup: "Horde WebDAV", I try to authenticate then but it 
doesn't work. I use app authentication method with IMP. I can easily log 
into Horde, but here it's doesn't work. I'm not sure, but there is 
nothing about that in log file:

http://horde.jurewicz.pl/horde.log

but I might miss something...

I'd be very gratefull for any help.
Wojtek