Can you show us a screenshot of the error message? And for the slow speed, what is the speed if you connect the pc to the modem via ethernet cable and what is the speed with 2.4G and 5G wifi...

For the QoS settings, we can click on Queue Config to set up the details. Details can be found in this link: http://www.tp-link.gr/faq-533.html And the Traffic control/ bandwidth control function is...

The TD-W8960N V7 don't support bandwidth control, so you cannot limit the bandwidth. But it support QoS, you may refer to this link to set high priority for online game to get better performance for...

What's the speed with wired connection? What's the firmware version? Have you tried to upgrade the firmware and change channel, channel width for wifi? Have you tested with different devices?

What's the hardware version and firmware version of TL-WR841N? What's the model number of your laptop and its wireless adapter? If you connect other wireless clients, like tablets, phones, to the...

What's the model number of your router? On TP-Link routers, normally we have MAC Filtering & Access Control function which can block devices. What requirement do you have for the new router? Do you...