How to Solve:
Please follow below steps to resolve client machine error

Note: Server IP Should be Fix Or Static o Server machine instead of Dynamic.
(Contact your IT person)

Case 1:
Screenshot 1: Go to Server machine >> Windows start button >> Search >> CMD >> Type ipconfig >> Press enter

Screenshot 2:  Now go to client machine
Right click on eZee Version 7 icon and go for open file location

Screenshot 3:
Screenshot 4:

Case 2: After setting IP address if it’s still shows problem with cannot access the database

Screenshot 1: Go to Server machine >> Windows start button >> My Computer >> Right click on computer >> Properties

Screenshot 2:
Screenshot 3:  Now go to client machine
Right click on eZee Version 7 icon and go for open file location
Screenshot 4:
Screenshot 5:

Case 3:
Go to Server machine >> Search  >> SQL Server Configuration Manager >> SQL Server Network Configuration >> Protocols for EZEENEXTGEN >> TCP/IP >> Enable >> Property >>Set port as 1433 >> Save
Related Link: Error: -1 A network-related or instance-specific error occurred while establishing a connection to SQL Server in eZee Frontdesk 7.0