Health Check has detected that the database connection string has been nulled for one of the following XenApp/XenDesktop Controller services:

ADIdentity Service
Analytics Service
AppLibrary Service
Broker Service
Configuration Service
Delegated Admin Service
Environment Test Service
Host Availability Service
Machine Creation Service
Monitor Service
StoreFront Service

For more information about these services, refer to CTX139415 -XenDesktop 7.x Services Overview

Run the following cmdlets to set the database connection string:

1. On the Delivery Controller, open a PowerShell command window.
2. Type `asnp  Citrix*`.
3. Type  `Set-[Service]DBConnection -DBConnection $connStr` (where $connStr is the connection string) 

Connectionstring examaple: Server=SQLServer; Initial Catalog=CitrixSitenameSite;Integrated Security=True

Note: If all services are nulled:, Delegated Admin, CentralConfig, ConfigLogging need to  first when set
7. Set-[Admin}DBConnection $connectionstring