In the classic version ( ) You could have been logged in under different accounts (3DWH, Extension WareHouse, even the Credits log-in).
Now, with 2019 you are bound to one: The one were your Subscription or Classic license is tied to.(TrimbleID)
You might have bought or downloaded several extensions under different (Google) Accounts and they might be not the same as the Trimble ID, you would need to merge them.:
) You could have been logged in under different accounts (3DWH, Extension WareHouse, even the Credits log-in).