Problems with HP Officejet 7500A and WP X8Pro in Win 10

First problem:  Erratic printing.  Sometimes I click on Print, the job is done and the printer prints just fine,  other times, the process takes a long time, yet other times, nothing ever prints and there is nothing in the print queue.  Sometimes, if I clear the print queue, even thought no jobs are showing, the printer returns to "normal", other times not.  The printer is on the network, but that does not seem to be the issue.  I do have the latest HP network drivers for this model.  Note that this process is not occurring on any other software, just WP8X.

Second problem:  cannot resize large format paper sizes.  I use 11 X 14 to print out certificates.  On the new PC with a clean installation of Win10, I cannot get the margins to change beyound default.  I do get an error message.  I have duplicated all WP setting from the old machine that did all me to change the margins. but so far no luck on the new PC.  Any ideas?