Cannot Create invoice or Quote Now

Hi, I have read each post on the forum with regards to creating an invoice error, my log has no errors on it, but for some reason, it does not allow me to create invoice or quote. chrome inpector gives me the following errors

Failed to load resource: the server responded with a status of 500 ()
dependencies.min.js?v=1.5.10:1 GET https://invoice.spiderwebhosting.co.za/index.php/quotes/ajax/modal_create_quote 500
send @ dependencies.min.js?v=1.5.10:1
ajax @ dependencies.min.js?v=1.5.10:1
D.fn.load @ dependencies.min.js?v=1.5.10:1
(anonymous) @ all:55
dispatch @ dependencies.min.js?v=1.5.10:1
m.handle @ dependencies.min.js?v=1.5.10:1
dependencies.min.js?v=1.5.10:1 GET https://invoice.spiderwebhosting.co.za/index.php/invoices/ajax/modal_create_invoice 500
send @ dependencies.min.js?v=1.5.10:1
ajax @ dependencies.min.js?v=1.5.10:1
D.fn.load @ dependencies.min.js?v=1.5.10:1
(anonymous) @ all:51
dispatch @ dependencies.min.js?v=1.5.10:1
m.handle @ dependencies.min.js?v=1.5.10:1

500-Errors are always most probably related to the Server/Setup and not to the application.
Pls check your ServerLogs.
Also pls update to v1.5.11 as its brings some improvements.

@M4rt1n thanks for the feedback, I have spoken to the server guys they stated nothing wrong with the server, will update to latest IPv1.5.11 and see if that is the reason for the error.

PS where can see see the change logs

It will not fix it. It can not. your problem is related to your Server and can not be fixed by Application Updates.

Just read the Wiki HERE

Pls just provide the Server-Error-Logs here so we can find the issue, everything else will not lead to the solution