You are probably logged in with a different email address (Trimble ID) than where your Subscription was purchased with. To check if your email address is already associated with a Trimble ID:
Go to https://www.sketchup.com. Enter the email address you want to check and click 'Next'.
Three things can now happen:
A. You will be prompted for the password: The Trimble ID exists and is active.
B. It says that the account is nearly ready: click on the link to send the activation email again.
C. You will be prompted for a Name and Password for the Trimble ID. A Trimble ID does not yet exist, follow the steps to create one.