some client just can't connect L2TP/IpSec

[tschmit]

pfsense: 2.4.4
client: windows 10pro 1909 native client

all seems fine until phase II:
05[IKE] <con-mobile|3662> CHILD_SA con-mobile{4715} established with SPIs c6543032_i f72232ce_o and TS 185.3../32|/0[udp/l2f] === 82.64../32|/0[udp/l2f]

then I get:
05[KNL] interface ng1 appeared
05[KNL] interface ng1 disappeared
10[NET] <con-mobile|3662> received packet: from 82.64..[4500] to 185.3..[4500] (76 bytes)
10[ENC] <con-mobile|3662> parsed INFORMATIONAL_V1 request 3401254334 [ HASH D ]
10[IKE] <con-mobile|3662> received DELETE for ESP CHILD_SA with SPI f72232ce
10[IKE] <con-mobile|3662> closing CHILD_SA con-mobile{4715} with SPIs c6543032_i (1165 bytes) f72232ce_o (1592 bytes) and TS 185.3../32|/0[udp/l2f] === 82.64../32|/0[udp/l2f]

and the tunnel establishment finally fails with error code 720.

other pcs with the same config can connect to the L2TP/IpSec VPN.

any suggestions are welcome.

[dcugy]

@tschmit I have same problem, client OSX 10.13 native client. All work fine with 2.4.4p3 but is broken with 2.4.5p1