We have seen connection issues from our Telkom LTE clients. This can also have to do with some Huawei routers.
We have found the following solution to work wonders:
The modem changes its public IP address every few seconds.
In your browser go to 192.168.8.1
If you haven't changed it, login is admin admin
Select Dial-up -> Profile Management
Click on New Profile
Give the new profile a name (not important what it is)
Leave User name and Password blank
Select IPv4 & IPv6 for IP type (Sometimes not needed)
In APN type unrestricted
Click Apply
Switch the modem off and on.
This should resolve your issue
