@VDSANTOS Hello, 

RE uses the same wifi password of router after it is being successfully set up. 

If the RE Led/ WiFi Leds are ON on the range extender, but wireless client will not accept the password of router:

• Download tp-link Tether app, double check Range extender's password on Tether app:  
• https://www.tp-link.com/support/faq/2541/
•  Change a different SSID for RE ( different from router's SSID) and reconnect to it use the password showed up on Tether app 
• Delete Wi-Fi profile/ Forget Wi-Fi on that device and put in Wi-Fi password again (for iphone : go to Settings-- WiFi, click on RE's wifi name and forget this network ) 
• Make sure that device could connect to main router's wifi with no pronlem.
• If only one device will not connect to RE's Wi-Fi, please contact corresponding support and reset your Wi-Fi settings on iphone/ TV 

If wireless device still reports an Error when connect to WiFi, please send us a photo of the Error and let us know the Led status on RE, thank you 

Hello  @Gogroomgo 

Here is a summary thread for IOS reporting Weak security concern:

[Solution] iPhone iOS14 recognizing the range extender wireless network as "weak security"
If your model is not listed, or you still experience the same issue, please start a new thread or leave your comment above.