How to delete users in the IQAN connect portal

I am having trouble trying to delete users that I have created and no longer need in the IQAN connect portal. 

When selecting the delete button on the user tab, a warning tab pops up to ask if I'm sure of deleting the user and when I select the delete button I get the error message 'Could not delete user' with no information as to why or how I can resolve this. Has anyone else had this issue and if so how can I resolve it?