Can you give me information about your internet browser and operating system? Do you have some addresses from router DHCP server?

http://www.tp-link.com/en/faq-557.html - did you read this thread?

TL-WR940N_V2_140627 - it's latest firmware for your router. When connecting a fairly large number of devices (8-9), it also requires its daily reboot, otherwise some devices drop in and out of...

Can you see some information from device about error connection?

W10 is test version for now

Are you trying router access by IP address?