What happened with this issue while connecting to personal hotspot?

I am attempting to connect to my personal hotspot, and after several attempts, it failed, and then pop up a window shows as the picture attached;

Here's for translation:

[Heading]

Wi-Fi Network "~" required WPA2 Password.

[Type-in Field]

Key:

<HERE IS HEXADECIMAL DIGITS>

Input totally 64 hexadecimal digits.

[Checkbox]

<Box> Show password

[Warning Sign]

Connection failed.

Comment: I am confused by the "Totally 64 hexadecimal digits", it is obviously not the language style of Apple's product, and what does the 64 hexadecimal digits mean? Why the passcode be replaced by the keys? Moreover, the UI shows this field in [Courier New] typeface.