Error "FATAL: sorry, too many clients already" reported in PostgreSQL for ThingWorx Platform

Unable to execute service SpotlightSearch on SearchFunctions : Unable to get search entries: [2,006] Unknown error occurred. Contact the administrator if this re-occurs.

FATAL: sorry, too many clients already

java.sql.SQLException: Connections could not be acquired from the underlying database!

java.lang.RuntimeException: com.thingworx.common.exceptions.DataAccessException: [2,006] Unknown error occurred. Contact the administrator if this re-occurs.
    at com.thingworx.persistence.common.DataTableEngine.lambda$findEntries$11(DataTableEngine.java:237)
    at com.thingworx.persistence.TransactionFactory.createDataTransactionAndReturn(TransactionFactory.java:161)
    ...
Caused by: com.thingworx.common.exceptions.DataAccessException: [2,006] Unknown error occurred. Contact the administrator if this re-occurs.
    at com.thingworx.persistence.postgres.PostgresDataExceptionTranslator.rethrowTranslated(PostgresDataExceptionTranslator.java:27)
    at com.thingworx.persistence.postgres.dao.PostgresDataTableDao.searchEntries(PostgresDataTableDao.java:292)
    ...
Caused by: java.sql.SQLException: Connections could not be acquired from the underlying database!
    at com.mchange.v2.sql.SqlUtils.toSQLException(SqlUtils.java:118)
    at com.mchange.v2.c3p0.impl.C3P0PooledConnectionPool.checkoutPooledConnection(C3P0PooledConnectionPool.java:692)
    ...
Caused by: com.mchange.v2.resourcepool.CannotAcquireResourceException: A ResourcePool could not acquire a resource from its primary factory or source.
    at com.mchange.v2.resourcepool.BasicResourcePool.awaitAvailable(BasicResourcePool.java:1507)
    at com.mchange.v2.resourcepool.BasicResourcePool.prelimCheckoutResource(BasicResourcePool.java:644)
    ...
Caused by: org.postgresql.util.PSQLException: The connection attempt failed.
    at org.postgresql.core.v3.ConnectionFactoryImpl.openConnectionImpl(ConnectionFactoryImpl.java:292)
    at org.postgresql.core.ConnectionFactory.openConnection(ConnectionFactory.java:49)
    ...
Caused by: java.io.EOFException
    at org.postgresql.core.PGStream.receiveChar(PGStream.java:308)
    at org.postgresql.core.v3.ConnectionFactoryImpl.doAuthentication(ConnectionFactoryImpl.java:499)
    ...