Validated the progress of the uploading from the sales journal to Ms. Myra. She advised that after restarting the NAV, the uploading time seems improved as she can upload 100 lines for 5-10 mins. I monitored the uploading of 500 and more lines as well and it just takes 20-30 mins unlike before when it takes overnight. Will keep on monitoring this as the workaround is restarting the NAV services.