Select the menu in the top right corner (≡).
Click on Preferences or Options
Select Privacy & Security from the lefthand menu
Go to the Cookies and Site Data section and click on the Clear Now
If you want to clear cookies only for the Convious URLs:
Under Cookies and Site Data, click on the Settings
Type Convious in the search bar and click on the Remove All Shown
Click on the Save Changes button
Close and reopen your browser