Dear @Daanishhh,

When I connect TL-R470T+ to a wireless / wifi router, and set the WAN mode of that router to Dynamic IP... It connects, but speed reduced like 200kbps or max 300kbps..  

It works fine if I connect to a PC / Laptop having windows, but it is not working as expected with wireless / wifi router.

Is the speed of 200kbps~300kbsp tested through a wired connection or through a wireless connection (2.4G or 5G)?

Did you try a different ethernet cable or other LAN ports for checking?

For the speed issue, you may check the information below.

1. When you connect TL-R470T ----wireless router, check the link speed from the TL-R470T router's web UI:

choose the menu Network ----> Switch ----> Port Status, where you can find the Speed(Mbps) of the corresponding connected port.

2. Connect TL-R470T ----wireless router ----PC (all with cable connection), then check the link speed on the PC:

How to check the associated/link speed on a wired client

3. Run speed tests on the PC 3 times through the cable connection to get an average result. Can you get a better speed?

4. Try connecting the TL-R470T router with a single WAN connection, then connect to the wireless router, check if it makes any difference.