The error in the Identity Portal during the IM main connector creation was the following:
Validation didn't pass, although the following action was ran: Config WS Configuration
The original IM main connector that was automatically created as part of the vapp deployment uses a Web Service Configuration ID value of "portal" and you had deleted this connector from the Identity Portal side and were trying to recreate it again within Portal but it was failing.
In the IM VST we could see the Create Web Services Configuration task was in an Audited state and had the following error message:
An error object was posted to the task with text: Unable to create Web Services Configuration - friendly name portal is not unique.
We checked in IM under the System->Web Services but could not see any existing however when we checked under the IM Admin Roles and IM Admin Tasks we still saw references to the "portal" objects that are created as part of the Web Service called "portal and so we manually deleted those Admin Roles and Admin Tasks. After this we were able to use Identity Portal to create a new IM main connector called "portal" successfully.