Helpdesk Request could not be sent

Helpdesk Request could not be sent

We just integrated ServiceDesk Plus MSP (professional) with our Desktop Central MSP (registered version). We've already configured ServiceDesk Plus MSP Settings successfully in Desktop Central. When submitting a ticket from an agent station through Send Request to Help Desk  on the system tray, the tickets goes to ServiceDesk Plus MSP - Request successfully but we keep on getting this error:

Helpdesk Request could not be sent. Contact your administrator to verify "ServiceDesk Plus Settings".



We also made sure Site name is the same with Remote Office name.