create gre tunnel to freebsd 11.2 problem

today i have client request;need create gretunnel between our route.
this’s mikrotik device config(demo environment):
please help look this,and fix it.

/interface gre> pri
Flags: X - disabled, R - running
 0  R name="to149" mtu=1476 l2mtu=65535 local-address=192.168.18.143 
      remote-address=192.168.18.149 dscp=0

/ip address> pri
#   ADDRESS            NETWORK         INTERFACE
0 171.1.1.1/30       171.1.1.0       to149 

[admin@NETMAY] /ip route> pri
Flags: X - disabled, A - active, D - dynamic, 
C - connect, S - static, r - rip, b - bgp, o - ospf, m - mme, 
B - blackhole, U - unreachable, P - prohibit 
 #      DST-ADDRESS        PREF-SRC        GATEWAY            DISTANCE
 0 A S  ;;; added by setup
        0.0.0.0/0                          192.168.18.2              1
 1 ADC  10.1.1.0/30        10.1.1.2        To142                     0
 2 ADC  171.1.1.0/30       171.1.1.1       to149                     0
 3 ADC  192.168.18.0/24    192.168.18.143  ether1                    0

and this is my FreeBSD Configuration command:

ifconfig gre0 create
ifconfig gre0 inet 192.168.18.149 192.168.18.143
ifconfig gre0 171.1.1.2 netmask 255.255.255.252 171.1.1.1
ifconfig gre0 mtu 1476 up

then i try ping the mikrotik gre tunnel ip:

ping 171.1.1.1
PING: sendto: No route to host


this is my FreeBSD route table:

Internet:
Destination        Gateway            Flags     Netif Expire
default            192.168.18.2       UGS         em0
localhost          link#2             UH          lo0
171.1.1.1          link#3             UH         gre0
171.1.1.2          link#3             UHS         lo0
192.168.18.0/24    link#1             U           em0
192.168.18.149     link#1             UHS         lo0

Internet6:
Destination        Gateway            Flags     Netif Expire
::/96              localhost          UGRS        lo0
localhost          link#2             UH          lo0
::ffff:0.0.0.0/96  localhost          UGRS        lo0
fe80::/10          localhost          UGRS        lo0
fe80::%lo0/64      link#2             U           lo0
fe80::1%lo0        link#2             UHS         lo0
ff02::/16          localhost          UGRS        lo0