@Tomochka 

Could you please let us know what kind of password do you mean?
1. If you mean the login password of your TP-Link device, it is recommended to try admin in lower case. However, if admin doesn't work and no other possible password, please reset your TP-Link device to default settings by pressing and holding the reset button for 10s. 

2. If you mean the Wi-Fi password of your TP-Link device, please use the default Wi-Fi password to see if it works. The default Wi-Fi password is printed on the label of this device itself as wireless password/PIN. If the default password doesn't work, please reset your device to factory defaults and try again.

  @Igor1980 

Hi, I assume you are able to login the Tether App but unable to login the router, right? For the router login password, it is the same as the one used to login web interface, if you don't remember it, please try admin in lower case.

However, if admin doesn't work and no other possible password, please reset your TP-Link device to default settings by pressing and holding the reset button for 10s.

Please note that all the configurations will be cleared after the factory reset, you will need to set up the router again.

  @Eduard74 

Hi, the local password to login the TP-Link device on the Tether App is the same as the one used to login web interface, if you don't remember it and admin doesn't work either, please reset your TP-Link device to default settings by pressing and holding the reset button for 10s.

Please note that all the configurations will be cleared after the factory reset, you will need to set up the router again.