2965367 - FAILED to allocate port: All 1000 ports defined by [50000-50499:50500-50999] are in use

• XSA applications fail to start.
• xscontroller and xsexecagent logs contain the following error:

Failed to adapt number of application instances.
...
Unexpected Exception in Execution Agent due to internal error.
com.sap.xs2rt.utils.LessResourcesException: FAILED to allocate port: All 1000 ports defined by [50000-50499:50500-50999] are in use

SAP HANA Extended Application Services, Advanced model

503 service unavailable, FAILED to allocate a port in port range [50000-50999], All 1000 ports are already in use by XSA, Please increase the port range defined by the properties 'listen_portrange_start' and 'listen_portrange_end' in xsexecagent.ini , KBA , BC-XS-RT , XS Advanced Runtime / XS Controller , Problem