@deraymaekerci
thanks for contribution
Which router model is installed:
Internet Box 3, - 2, - plus, - standard, - light, other?
My internet router - Help | Swisscom
Which TV box model is installed:
Swisscom Box 21, Swisscom Box, TV-Box UHD, TV-Box HD, others?
Swisscom blue TV: devices & instructions - Help | Swisscom
What is the connection mode between router <-> TV box:
Ethernet cable, WiFi, Powerline connection kit, others?
Very often a RESET / REBOOT of the various installed devices enables a normal situation to be restored.
Despite everything, if it were not, one of the devices could be defective and must either be replaced with the same model or with a newer model.
It is also possible that the connection mode of the router <-> TV box is not suitable for the configuration of the house. Always prefer the Ethernet cable. If this is not possible, it is sometimes necessary to install a WLAN box to ensure better stability and performance of the connection.