FWIW: You cannot perform this "force logout:" that ZhaoKai suggested unless you are the "License Admin" for your organization. If you are not, then you need to contact that person (or their delegate) to help you.
Note: As a last resort ... You can always try the Appeon Website's "CHAT" feature and ask the the online support person if they can do the Logout for you.
It's might cause by your account is still logged in on other PC. You may either log it out from other PC or do a forced logout from the User Center in the Appeon website (https://www.appeon.com/user/center/index), and then try again. You may refer to the below help for more details: https://www.appeon.com/support/documents/appeon_online_help/pb2017r3/appeon_license_user_guide/logging_out_users.html