Thank you for contacting us, and I'm sorry for the issue you're experiencing. When you say you reset your passcode, can you describe you did that? Did you open mSecure, go to the Settings and tap the "Change Password" option, or did you reset your account from our website?
It could be that you're running into an issue because you reset your account, but since I'm not sure if you did that or not, I don't have any idea what could be causing it to happen. Before I have you look for a backup file to restore your data from, please open mSecure and then tap the menu button in the top left of the app. After the menu slides in, what number do you see to the right of "All Items"?
Let's try having you restore your data from a backup stored in your iCloud account. Open mSecure, then tap the menu icon in the top left of the screen. Tap Settings, then in the Settings screen, tap Backups. In the list of backups, tap the most recent file, then tap Restore.
Were you able to restore your data from a backup?
I was afraid this was going to happen. The reason the password is not working is because the data stored in the backup is encrypted with the old password from before you reset the account.
I just checked your account in our system, and I'm not seeing any encrypted data stored online, so that means the data was fully removed from your account. This would confirm an account reset was processed from our website. If the password is changed from inside mSecure's Settings, data is not removed from the account. However, if the account is reset from our website, then the data is deleted from the account. The data has to be deleted, because the new account key that is created after an account reset will not be able to decrypt the data stored in the account. Since the data cannot be decrypted, it is simply destroyed and the account is set to a fresh state.
Unfortunately, in these situations, the only hope of getting the data back is to try restoring from a backup file like you have already done. We don't have access to your account password, the account key, or any of your decrypted data, so there's no way we can retrieve it for you. I'm really sorry I don't have better news here.
Do you have any idea what your old password could be? If you do, is it possible you need to substitute a character like $ for S or 3 for E? Sometimes that can help in remembering the correct characters for a forgotten password.
Backups are encrypted using the password data used at the time the backup was created. In this case, the password that would be needed to restore from the backup would be the old password. Any backups that may have been created automatically since the account reset would not contain the data you are trying to retrieve.
Regarding character requirements, the password must be at least 4 characters in length, and that's it. When setting a password in mSecure, there is information provided to guide you to creating a much stronger password, but the only enforced requirement is that the password is 4 characters long. And to be clear, the 4 characters can be any characters you choose.