L2TP Over IPSEC Problem

RouterOS General
1

Dear all,
I can’t connect to my 750G r3 router after October from China,

recently I checked the Log, it shows as following:

Time Nov/13/2017 00:23:04
Buffer memory
Topics ipsec,info
Message respond new phase 1 (Identity Protection): ROUTER IP[500]<=>CURRENT IP[> 60865> ]

Time Nov/13/2017 00:23:07
Buffer memory
Topics ipsec,info
Message > the packet is retransmitted by CURRENT IP[60865].

Time Nov/13/2017 00:23:11
Buffer memory
Topics ipsec,info
Message > the packet is retransmitted by CURRENT IP[60865].

Time Nov/13/2017 00:23:14
Buffer memory
Topics ipsec,info
Message > the packet is retransmitted by CURRENT IP[60865].

Time Nov/13/2017 00:24:04
Buffer memory
Topics ipsec,error
Message phase1 negotiation failed due to time up ROUTER IP[500]<=>CURRENT IP[60865] xxxxxxxxxxxxxxxx:xxxxxxxxxxxxxxxx

then the connection was closed.

And if I connect to my Router from any other place outside from China, it shows as following:

Time Nov/13/2017 00:42:47
Buffer memory
Topics ipsec,info
Message respond new phase 1 (Identity Protection): ROUTER IP[500]<=>CURRENT IP[500]

Time Nov/13/2017 00:42:47
Buffer memory
Topics ipsec,info
Message ISAKMP-SA established ROUTER IP[4500]-CURRENT IP[4500] spi:xxxxxxxxxxxxxxxx:xxxxxxxxxxxxxxxx

Time Nov/13/2017 00:42:48
Buffer memory
Topics l2tp,info
Message first L2TP UDP packet received from CURRENT IP

Time Nov/13/2017 00:42:49
Buffer memory
Topics l2tp,ppp,info
account
Message xxxx logged in, 192.168.xx.xx

Time Nov/13/2017 00:42:49
Buffer memory
Topics l2tp,ppp,info
Message : authenticated

Time Nov/13/2017 00:42:49
Buffer memory
Topics l2tp,ppp,info
Message : connected

then the connection will be established successfully.

I noticed the red words are different from normal connection.
is this because of the L2TP/IPSec connection pollution?
is there any solution for this?