Welcome to the Bose Community, thanks for taking the time to post.
I am sorry to hear you are having issues signing into the Bose Music app.
I should advise, the account information for the Bose Community is not linked, so being able to log in here will have no effect in relation to being able to log into the app.
With regards to this issue, however, can you please try to uninstall the app from your device, then re-download it, then attempt to sign in again? If possible, please try with another smartphone, also.
I'll look forward to hearing from you and if anyone else has any other suggestions, please feel free to join in the discussion.