Why is my password being rejected?

For security reasons, passwords must be at least 10 characters in length and comprised of upper and lowercase letters, numbers and symbols.

That means the password must be a combination of:

Lowercase letters (a-z)

Uppercase letters (A-Z)

Numbers (0-9)

Symbols ( !”#$%&'()*+,-./:;<=>?@[\]^_`{|}~ )  

Note that the symbols account for most standard keyboard symbols, but not necessarily phone or non-english keyboards. Generally, symbols on the number keys are a safe bet.