AxCrypt has a sophisticated password strength evaluator based on measuring the actual strength of the password. It must also be at least 8 effective characters long.
We evaluate the password by estimating the strength, which is based on how long and complex the password is.
The evaluation entirely disregards parts of the password that is recognized as being among the 1,000 most common passwords, as well as white space.
I suggest you use the ‘show password’ option in both the web and the app, and ensure that what is type is truly identical. This means having the same casing, the same spacing, the same umlauts and accents etc.
You can AxCrypt Password Generator to generate a strong password: https://www.axcrypt.net/password-generator/