WHMCS support are being extremely slow so I thought I'd try the general public.
Several pages are giving a 500 error message with this message in error_log:
[Thu Dec 09 18:54:19 2010] [error] [client ] Premature end of script headers: cart.php, referer: http://x.com/billing/index.php
On the pages:
https://www.x.com/members/clientarea.php
and when ordering. I have had the error on other pages though.
When logged in as admin I can access these pages, however after upgrading to 4.4.1 I'm getting the 500 error after logging into admin.
The errors seem pretty random to me. I've reinstalled WHMCS many times but it hasn't fixed anything. All my permissions are correct. All other PHP software works fine, it's just WHMCS, which is making me think that there's an error in the code.
Any recommendations?