VR900 is the main modem, is the DSL light solid on when it drops? Make sure the modem is working properly at first.

How do you test the speed? Just connect one client to the router via a cable or wirelessly? If you connect your pc to your modem directly, how about the speed?

? what's your model number?

Do you remotely login the web UI of this router? If yes, it will be normal and we need to update firmware from local access.

Do you mean it requires a web page authentication? If yes, TL-WR841N does not support the portal wifi. If you mean the PPPoE dial-up, you can set LT-WR841N as a wireless router and choose PPPoE...

1. make sure you do connect the 2.4G wifi network from MR200. 2. try to change another wireless channel for 2.4G wireless network? 3. make sure there is no any mac filtering setting on the router.