Here are some of the quick checks that could be carried out:
- Login to the ISA Management Console and ensure that the ISA Gateway (through which the AD/LDAP server is securely accessed) is Online under the Live Gateways Report
- Check whether the AD/LDAP servers configured for the Authentication Profile in the ISA Console are reachable from the ISA Gateway Server (typically default LDAP authentication port TCP 389 is used)
- Depending on the type of deployment, ensure the NAT rules on the ISA Gateway or the static routes for ISA on the network router (default gateway) are correctly configured and in place
- Check whether the sync component 'InstaSafe Helper' is Online under Live Users Report