ERROR when opening "Create Form" with Rich Form

Error:

"Unrecognized content type:text/html;charset=UTF-8" comes when we click on Create Form after selecting Form Type Rich Form

Cause:

Improper permissions within installation directory

Solution:

Provide the recursive Read and Write permissions to the RichForms folder located at "\AdeptiaSuite-6.0\AdeptiaServer\ServerKernel" and then try to create and edit a Rich Form