BGP peering doesn't come up with /31 subnet

• BGP peer stays in ACTIVE mode and doesn't move to ESTABLISHED state.
• Noticing below logs in the var/log/pan/routed.log

  **** PROBLEM     0x0303 - 20   (0000) **** I:000015c6 F:00000001
  sckrecv2.c 1968 :at 11:03:37, 15 June 2021 (410673 ms)
  Failed to connect to remote address.
  Sockets error code = 101
  Remote address     = 10.20.0.47
  Remote port        = 179
  Socket ID          = 1565
  Socket type        = 0X00000001
  Socket family      = 0X00000002
  Socket protocol    = 0X00000000
  Stub socket handle = 0X2DA40000
  Application handle = 0X03B40000

• Palo Alto Firewalls
• Supported  PAN-OS
• BGP peering with /31 subnet.

• This is expected behavior as routing is not supported over  /31 interfaces.
• When BGP session is initiated by the peer with /31 subnet, socket is not created and no packet is sent out to the peer. Socket error is "101 = Network is unreachable"

Use /30 or other subnets for BGP session to be established.