pptp vpn often dropped out
I'm a newbee on digitalOcean.I created droplet for vpn(pptp).
I set vpn as here
Firstly,i added 2 vpn accounts on the server /etc/ppp/chap-secrets file,one for pc and another for mobile phone.
Then i try to get the connection on a pc(ubuntu system).It's successful.
But it dropped out after about 6 minutes later.
I found that when the pc is connected and if i connect the vpn on mobile phone,the pc would drop out and mobile phone would connect failed.
Though i have connected the vpn on he mobile(pc is ok with it),the speed is too slow.
Could someone help me?Thank you very much!