StrongSwan and Bird BGP route propagation

Question

I have the following networks successfully connected through IPSec StrongSwan tunnel (ie. I can ping both sides through private IP addresses):

VPS1: 192.168.8.44 -- VPS2: 192.168.1.21

I want to advertise 192.168.8.0/24 network on VPS1 side and 192.168.1.0/24 on VPS2 side through BGP.

I installed bird and configured it on the both sides. Here is excerpt of config from VPS2 side, other one is identical, just IPs are changed:

protocol static {
  route 192.168.1.0/24 via 192.168.1.21;
}

protocol bgp {
    import all;
    export all;
    local as 65002;
    neighbor 192.168.8.44 as 64514;
    multihop 1;
}

But this is not working. From VPS1 BGP session is established correctly:

bird> show proto
name     proto    table    state  since       info
kernel1  Kernel   master   up     17:26:26
device1  Device   master   up     17:26:26
static1  Static   master   up     17:26:26
bgp1     BGP      master   up     17:26:30    Established

but show route shows unreachable:

bird> show route
192.168.1.0/24     unreachable [bgp1 16:26:30 from 192.168.1.21] * (100/-) [AS65002i]

In the logs following warning appears:

Next hop address 192.168.1.21 resolvable through recursive route for 192.168.1.0/24   

what does it mean? what am i doing wrong? I can ping 192.168.1.21 just fine.