This can happen when the log in screen has already selected the first drop down (i.e. it is outlined in blue). To resolve the issue in a one-off instance, click somewhere else on the window that takes the cursor off the first drop down. If all your devices have the same element already selected, you can modify the code. For the the v57 and below script, you will make the edits on line 139. With version 58+ you will make changes to line 176. You will need to change the number of TAB presses required by your devices to get to the Networks menu rather than Accessibility.