Please assist
as soon as I click on payments or shipping tab in the backend I get a 500 internal error
I enable debug and maximum error reporting but I don't get any other error.
Which Joomla/VM/PHP versions. What is the exact 500 error? Look at error log.
Stan from Rupostel produced a very useful Fatal error plugin that emails the error to you if you can't find the logs.
https://www.rupostel.com/utilities-for-joomla/extensions/fatal-catcher-plugin
It used to happen when some overrides were present.
For some reason the plugins don' get the right tempalte layout
Have a look at
https://forum.virtuemart.net/index.php?topic=150199.0