IPsec/XAuth [AES_CBC (256), HMAC_MD5, MODP1024] refused

[chengwei20]

May 2 08:58:41 ubuntu-s-1vcpu-1gb-sfo2-01 pluto[410]: deleting connection "xauth-psk"[1] ×××× instance with peer ×××× {isakmp=#0/ipsec=#0}
May 2 08:59:19 ubuntu-s-1vcpu-1gb-sfo2-01 pluto[410]: "xauth-psk"[2] ×××× #3: responding to Main Mode from unknown peer ×××× on port 887
May 2 08:59:19 ubuntu-s-1vcpu-1gb-sfo2-01 pluto[410]: "xauth-psk"[2] ×××× #3: Oakley Transform [AES_CBC (256), HMAC_MD5, MODP2048] refused
May 2 08:59:19 ubuntu-s-1vcpu-1gb-sfo2-01 pluto[410]: "xauth-psk"[2] ×××× #3: Oakley Transform [AES_CBC (256), HMAC_MD5, MODP1536] refused
May 2 08:59:19 ubuntu-s-1vcpu-1gb-sfo2-01 pluto[410]: "xauth-psk"[2] ×××× #3: Oakley Transform [AES_CBC (256), HMAC_MD5, MODP1024] refused
May 2 08:59:19 ubuntu-s-1vcpu-1gb-sfo2-01 pluto[410]: "xauth-psk"[2] ×××× #3: OAKLEY_GROUP 1 not supported. Attribute OAKLEY_GROUP_DESCRIPTION
May 2 08:59:19 ubuntu-s-1vcpu-1gb-sfo2-01 pluto[410]: "xauth-psk"[2] ×××× #3: STATE_MAIN_R1: sent MR1, expecting MI2
May 2 09:00:19 ubuntu-s-1vcpu-1gb-sfo2-01 pluto[410]: "xauth-psk"[2] ×××× #3: deleting incomplete state after 60.000 seconds
May 2 09:00:19 ubuntu-s-1vcpu-1gb-sfo2-01 pluto[410]: "xauth-psk"[2] ×××× #3: deleting state (STATE_MAIN_R1)

初步感觉是libreswan的ipsec.conf配置问题，但是不知道如何解决。
感谢。