Invoices not displaying

[Vanguard]

I am having an issue where all invoices, old or new, do not display (no php, no html). In other words the URL ending in "admin/invoices.php?action=edit&id=XXXX" has no output.

 

Not sure when the issue started as most customers are on yearly or automatic payment plans. The last changes to the system were the upgrade to WHMCS 5.1.2 and an upgrade of the addon FREE ResellerClub Tools v2 and things were working before those two changes.

 

I have several new customers that I need to invoice so I obviously need a solution ASAP.

 

Any idea where to start, or steps to follow, for trouble shooting?

 

Thanks, Richard

 

 

Configurations:

WHMCS: 5.1.2

MySQL: 5.1.65

PHP: 5.3.15

Apache: 2.2.22

 

WHMCS Addons:

• Google Analytics Integration
  
• PayPal Addon
  
• FREE ResellerClub Tools v2
  
• enom PRO Addon
  

[Vanguard]

Additional info:

 

Internet Explorer displays a cannot read this webpage format message (but other browsers show only a blank page — no source code) with the following more info:

 

This error (HTTP 406 Not Acceptable) means that Internet Explorer was able to receive information from the website you visited, but the information was not in a format that Internet Explorer can display.

 

I have enabled PHP Error Reporting within WHMCS as part of trouble shooting and there is no error reported when calling up the invoices.

[Vanguard]

An update:

 

I have noticed that I can view one invoice within the WHMCS admin area and the client area.

 

The invoice happens to be for a $0 amount.

 

Every other invoice can not be displayed within the WHMCS admin area or the respective client area and significantly, or not, is for a dollar amount.

[Vanguard]

Well could not put off invoicing any longer.

 

Over wrote upgrade with pre-upgrade back up and I am up and running again.

 

So, what damage have I done and need to now fix? Where I am running old version files and the software thinks it is running the latest version.