Some days back it happen to me. Yes, suddenly my client told they changed all the IP of all the servers and then am not able to up the informatica services.
The major reason behind this problem is in nodemeta.xml file IP has been mapped with database server.
Follow the below steps and restart the services.
Open the Workflow Manager Client
Click the 'Connection' menu option along the top and then select 'Relational'
This is where the Database settings are set
Additionally, also you may need to modify the 'nodemeta.xml' file for your Informatica Services .