PPTP client access question

Hi,
I have a RB951UI as a PPTP server and on the other side I have a RB951UI as PPTP client using 4G Huawei USB stick to connect to internet and a Teltonika RUT950 as PPTP client using again 4G sim to connect to internet.

After proper setup Im able to ping both PPTP clients from a PC connected on PPTP server router but I cannot access the Huawei HiLink interface on first router and Teltonika interface on second router.

It looks like it works but browser stops after many seconds (maybe minutes) when it redirects on start page of the above devices.

Any ideas?