If your organization created a custom-branded app with their name and logo, you might be using a login system that is managed by your organization.
Try these steps to troubleshoot:
Make sure your username is correct and you have no extra spaces added before or after. This can happen if you are copying and pasting your credentials.
If there is an eyeball icon to the right of the password field, tap it to make your password visible. This can help you check that you typed it accurately.
Try tapping Forgot password? if that option is available. This will help you reset your password.
If you are still having difficulties, please reach out to your organization for help.