How to fix the Oracle error TNS-12527: TNS:listener: all instances are in restricted mode or blocking new connections?

In this post, you’ll learn more about the Oracle ErrorTNS-12527: TNS:listener: all instances are in restricted mode or blocking new connections with the details on why you receive this error and the possible solution to fix it.

Oracle Error Description

TNS-12527: TNS:listener: all instances are in restricted mode or blocking new connections

Reason for the Error TNS-12527: TNS:listener: all instances are in restricted mode or blocking new connections

Cause: All appropriate database instances supporting the service requested by the client reported that they either were in restricted mode or were blocking the new connections. The Listener does not allow connections to such instances. This condition may be temporary, such as at instance startup.

How to fix the Error TNS-12527: TNS:listener: all instances are in restricted mode or blocking new connections ?

You can fix this error in Oracle by following the below steps

Action: Attempt the connection again. If error persists, then contact the database administrator to check the status of the instances.