When setting up Aruba Mesh with instants do not forget to turn off extended SSID.

Steps

1. Create cluster with IAP let them sync with image and configuration (update them to lateist code)
2. Disable the extended SSID ( in the latest version 4.x, it is enabled) in options
3. you will find both the IAPs as mesh portals.
4. Remove the IAP from the Switch which you want to make mesh point and provide external power.
5. After booting, there will be a mesh link between two IAPs.