Does it come from the many who are now working from home? My internet has been crashing for days despite 50,000 lines. I can't even watch netflix or youtube in peace and it makes me angry to pay 40 euro for nothing.
How about more information?
Whether you are connected to LAN or WLAN, for example.
or whether you use a repeater with WLAN.
If a lot of people access large amounts of data over the Internet at the same time, the data transfer rate is reduced. This can mean that films, especially in HD format, can no longer be streamed. You can perform a so-called https://speedtest.vodafone.de/#speedtest_start at different times and document the measurement results. This then gives you the opportunity to complain to your provider. The provider will now try to improve the situation. However, if the contractually regulated availability is not reached within a reasonable period, you have a special right of termination.