I'm in cable Germany (now belongs to Vodafone as far as I know) with my 50Mbit DSL connection. This has worked wonderfully for the last 4.5 years. My router was provided to me by Kabel Germany. Model: CVE-30360 The router has 4 ports for LAN cable outputs and I use them (so I do not use Wi-Fi). Everything wonderful the last 4.5 years but currently it is so that I can call daily between 8pm and midnight only a few pages. YouTube is still working. Google too, but only the search itself, but if you then click on a search result, - the call does not work! EbayKleinanzeigen still works partially (not all images are loaded / displayed). The T4 Forum is accessible. Thousands of pages are not available: Ebay, ZDF, Amazon, GMX, mirrors, weather, chess, Postbank, etc. Now it is even curious: All this as described on my Windows 10 PC on the LAN cable hangs. At the same time hangs on another LAN cable on the router my laptop with PuppyLinux 8, and on the laptop is not a single page accessible at the same time. (!) That's perhaps the strangest thing about it. Both computers are currently supplied with updates and both have Firefox up to date. On the Windows10 PC, I have still tested the Microsoft Internet Explorer, but that made no difference to the Firefox browser. What can be the mistake here? Why these dropouts only between 20 and 0 o'clock in about? Yes and why are some sites still accessible and others are not? And why is not a single page accessible on the laptop with Linux? The landline phone is still working in the event of a fault, so between 20 and 0 o'clock in about, flawless.
How about a call to the customer support of Kabel Deutschland?
That's exactly what it is for!
Note: The customer service may also have certain opening / service times, so call accordingly during the day and take time for it.
I would not have come in 10 years… It was about ideas and explanations, why it could be. I do not need anyone who tells me to call the customer support!
This is of course something in the blue shot but I could imagine that it is the DNS server? Maybe you should test as another time or assign manually to your devices. Maybe the DNS assigned to you by the ISP sometimes causes problems with the domain resolution of some pages…
Try the "8.8.8.8" which is from Google and is quite performant and reliable.
Thanks, I'll try that!