@anuragpodder Hi, have you tried accessing the Internet via Ethernet cable of the main router? If the disconnection occur only when you connect to WIFI using T3U, then you could refer to Case 2 of...

@Dipstick60 Hi, have you tried accessing the Internet via Ethernet cable to the Range Extender or via Wi-Fi of the main router? It's important to confirm whether the trouble took place in the RE or...

@Ravisbs_2008 I think you may hold the reset button on RE for more than 5 seconds, and then reconfigure it referring to https://www.tp-link.com/support/faq/1373/

@Ballamurugan Well, more details may be needed to pinpoint the issue. Are you having trouble during the initial configuration of the extender? Or the WIFI of extender disappeared suddenly during...

@MatiasVaisman Generally speaking, the transmission distance of 5GHz WIFI is far more shorter than that of 2.4GHz. So, any chance that you have placed the RE200 at a place far away from router? Or...

@Samuel_456 There is already a beta firmware that might help with the current issue, seeing this thread: https://community.tp-link.com/en/home/forum/topic/628396 You could install it and give it a...