When clicking the Add-ins > ChemACX Explorer option you may be prompted to login to Signals Notebook.
Even if you have a login for Signals Notebook, after entering the credentials you will get an access denied error:
To correct this error, please follow these steps:
1. Open ChemDraw Professional
2. Go to File > Preferences
3. Select the Cloud option
4. Change the ChemDraw Cloud URL to
5. Click OK and try again