Unable to connect to print/email invoices

Hi, I have had this problem before and came to the Forum and the solution worked, which was to back up and then reload back up onto the desktop and then open the print/email invoices tab and then send all the invoices from here, then back up again and put the file back in the cloud. I have done this and cleared, then I can open it and if I just import one invoice, it locks it up and I can't open the print/email invoice. I need to send over 150 invoices a day, to send them individually is not an option. Can you please help me? Thanks, Penny