Create new quote does but remains in the create page

Support
4

I created three quotes from the Submit page

cat /var/log/apache2/access_log

::1 - - [29/Dec/2015:16:22:03 +0100] "GET /InvoicePlane_v1.4.4/quotes/ajax/modal_create_quote HTTP/1.1" 200 124725
::1 - - [29/Dec/2015:16:22:08 +0100] "POST /InvoicePlane_v1.4.4/quotes/ajax/create HTTP/1.1" 500 1767
::1 - - [29/Dec/2015:16:28:24 +0100] "POST /InvoicePlane_v1.4.4/quotes/ajax/create HTTP/1.1" 500 1767
::1 - - [29/Dec/2015:16:28:36 +0100] "POST /InvoicePlane_v1.4.4/quotes/ajax/create HTTP/1.1" 500 1767

nothing in cat /var/log/apache2/error_log, cat /var/log/apache2/invoiceplane-error.log , cat /var/log/apache2/invoiceplane-access.log at these times