Could not load file or assembly 'X'
There are several causes for this issue.
Solutions:
Try recommendations in the following sections:
Type ‘X’ exists in both assemblies / Type ‘X’ is ambiguous in namespace ‘Y’.
Could not load file or assembly ‘Microsoft.Windows.Design.Extensibility …’.
Ensure that you copied DevExpress assemblies into the website’s Bin folder after the website is deployed on the production machine. You can use the DevExpress Assembly Deployment Tool to deploy assemblies.