Try to reset it, if no change, check if it's still under warrranty, contact TP-Link for replacement.

Hi Friend, It depends on you, please confirm waht's the operating system of your computer, make sure it's compatible with the adapter.Nowadays, internst speed is faster and faster, TL-WN821N should...

It's very important to get hte correct hardware version. You can click on the following link to get some help: https://www.tp-link.com/en/faq-46.html

What's the TP-Link device that you have? MP459?

try to change teh DNS in the web based management page, change dns to 8.8.8.8

Hey firend, I am using 180502, it seems perfect.