I can't connect to PPTP with a certain provider, what could be the matter?

Question

VPN

Raised PPTP on CentOS. everything is ok, I came from a mobile phone and from a PC, in another house with another provider I try to connect to my PPTP network and does not want to, there is no connection.
The logs on the server only have data about ms chap 2 , some problems with the protocol

asyncmap 0x0 auth chap MS-v2

It tries to connect without success, why it is not clear
. Also, I changed the pptp network address and nothing has changed either.
Googled for a long time, they say the problem may be in the configs in chap-secrets , so I didn’t find anything

Answer 1

some problems with
asyncmap 0x0 auth chap MS-v2 protocol

This line does not mention any problems.
~ 90% for the fact that the provider does not skip the GRE protocol, PPTP will not work without this protocol.