two Raspberry Pi 2 units - frequent disconnects from the Team Viewer service

I have two Raspberry Pi 2 units working with Team Viewer Host for this devices. The OS is the latest Raspbian. The Host app is the latest.
Since two months there is frequent disconnects from the Team Viewer service, and I can't manage both devices.
They are connected to the internet through a wireless repeater/extender, if this matters.
I have windows devices working in similar conditions and there's no problem with them.
I have tried to reinstall the operating system of one of the raspberries, but the problem persist.
It happens when the Raspberry itself has internet connection when the link is back. The network settings are default for the Raspbian OS, the wireless network has master router with DHCP, and the repeater is with auto DHCP - all equipment is TP-Link.
The Host app screen shows "not ready" state. Once it happened to show that the device is not link to any account after the disconnection.
 
What could be the possible solution?
 
Thanks in advance!