Basic PAYE tools error on entering an employee payment after update

I just updated to the latest version of Basic PAYE tools and now when trying to enter an employee payment I am getting "A server error occurred. Please contact the administrator'. Can anyone help?

Hi Jeremy Matheson,
Please contact HMRC online Service Helpdesk on 0300 200 3600 who can assit you with this.
Thank you. 

Thanks for the response. I found out that after restarting my Mac it worked fine. A restart was not required with updates before but now obviously with the browser integration or for some other reason it is now needed - will now know for next time.