If you have selected “Print Label “ and the print preview dialog box has only appeared as a blank screen before disappearing while using the Firefox browser, you will need to adjust the PDF options in the Firefox settings.
After selecting "Print Label" it may show a blank print preview dialog box, as shown below, before disappearing.
To change the settings, select the 3 menu lines in the upper right-hand corner, then select “Settings” from the drop-down menu.
Scroll down to "Files and Applications".
Under the "Content Type" column locate "Portable Document Format (PDF)", in the Action column to the right select "Open in Firefox".
Your labels will now pop up with the printing option at booking or reprinting labels from the History/Track page.