VPN Client ISSUE

Dear All

we had connected to a vpn server on asus router using vpn client in mikrotik
since yesterday we have problem in our connection and vpn client interface in mikrotik cant connect to asus vpn server
asus vpn server thrown this error in log :

2018-05-02 01:52:34 pptpd[16416]: CTRL: Client control connection started
2018-05-02 01:52:49 pptpd[16416]: CTRL: EOF or bad error reading ctrl packet length.
2018-05-02 01:52:49 pptpd[16416]: CTRL: couldn’t read packet header (exit)
2018-05-02 01:52:49 pptpd[16416]: CTRL: CTRL read failed
2018-05-02 01:52:49 pptpd[16416]: CTRL: Asked to free call when no call open, not handled well
2018-05-02 01:52:49 pptpd[16416]: CTRL: Couldn’t write packet to client.
2018-05-02 01:52:49 pptpd[16416]: CTRL: Couldn’t write packet to client.
2018-05-02 01:52:49 pptpd[16416]: CTRL: Client control connection finished

other device such as my mobile from different internet service can connect to the asus vpn sever but our mikrotik cant !!!

whats happening ?

vpn type : pptp
mschat1 checked
mschat2 checked
pap checked
chap checked

any idea?

Try mschapv2 on both side, encryption must be MPPE 128 bits on both sides(better be) and check mtu on both sides, must match.