If you are receiving the dreaded 500 error, you can follow the below temporary patches to display the detailed error in your browser. NOTE this can be a security issue if you leave these edits inplace, we do not take responsibility if you use these edits and leave them active.
1) create a web.config file in the root of the website if one does not exist and past this into the web.config and save it this will show detailed error messages in the remote browser
<?xml version="1.0" encoding="UTF-8"?>
<configuration>
<system.webServer>
<httpErrors errorMode="Detailed" />
</system.webServer>
</configuration>
2) if an existing web.config exists, you can edit the existing file and add the following in the namespace
<?xml version="1.0" encoding="UTF-8"?>
<configuration>
<system.webServer>
<httpErrors errorMode="Detailed" /> <<<<<<<<< add this line into the web.config under the first entry
</system.webServer>
</configuration>
----> other entries will be in here but DO NOT edit them as they will be required for your site to work.
NB !!!!!! remember to remove these edits once the site is running ok, as this will expose information to remote users and the potential to display critical information is always possible.