Please make sure that you are using the correct seed phrase, even a single space or character (even if you click on the Return/Enter button when you are importing the seed phrase) will generate another waves address. One seed phrase generates only one waves address.
If your phrase contains a space at the end ща line or pressed Enter/Return button, be careful, Beta application does not recognize additional characters at the end of the line since the standard phrase does not contain such characters.
By the way, the seed phrase always contains 15 words with spaces between each word. Except the beginning of the first word and the end of the last word.
For example (check attachments):
With one space>
With the pressed Return button
Customer support service by UserEcho