have you checked settings in security profile 

Yes,
That is the Security Profile:

not sure then sorry - as that was my issue too.

Craig,
Thank you for your help, I found the error, I should`ve set as true the "Allow Office Document Upload" as the picture below:

The error should be "No permission", rather "Unsupported media type", but ok!
Thank you,

Regards,

Hi All, Am facing exactly the same error.However if  i check the settings in the security profile the options of "Ällow Office Document Upload" are greyed out for the Administrators ,how can i activate this option?Am in Version 11

Sage factory created security profiles do not give modification access to this field. You will need to create a new security profile and assign it to have control over setting this field.

Andrew,Thanks for the feedback.Do you mean creating a  new security profile  and assigning to the admin?

Yes create a new security profile. In actuality, you're assigning it to the Syracuse role that needs these permissions. You may assign it to the customer or super admin role if needed, otherwise assign it to the role that needs office permissions.

Be careful to ensure that the security profile authorization permissions are the same as the one you are replacing (especially if replacing the security profile in super admin). Otherwise, you may inadvertently lock yourself out of making admin level changes due to a lack of permissions.