ORA-12545: Connect failed because target host or object does not exist

This error message indicates that the client was not able to establish a connection with the server because the target host or object does not exist. There could be several reasons for this error, including:

1. Incorrect hostname or IP address: The client may have entered an incorrect hostname or IP address for the server.

2. Incorrect port number: The client may have entered an incorrect port number for the server.

3. Firewall blocking the connection: The client may be behind a firewall that is blocking the connection to the server.

4. Server is down: The server may be down or not responding to requests.

5. Network connectivity issues: There may be network connectivity issues between the client and the server.

To resolve this error, the client should verify that they have entered the correct hostname or IP address and port number for the server. They should also check if there are any firewall rules blocking the connection and ensure that the server is up and running. If the issue persists, they should contact their network administrator or the server administrator for further assistance.