hello, here is what someone else had stated to it fixing the issue, however it didnt end up working for me or maybe i was just doing it wrong.
“Just for anyone downloading this plugin the error is still there. You can fix it easily by goign to line 107 and at the end (line 108 pending on your editor) remove the ‘?>’ and place it above the call i.e. in line 106
It worked for me so hope it helps. Great plugin thank you”