1. Host Not Found

1. Description: The DNS server was unable to locate the requested lookup address.
   
2. Possible Causes: This may happen if the hostname is incorrect, the domain does not exist, or there is a network or DNS configuration issue.
   
3. Troubleshooting:
   
1. Verify the hostname and domain name are correct.
   
2. Use nslookup <hostname> in a command prompt from the Applications Manager server to manually test DNS resolution.
   
3. If nslookup was successful resolving the IP address, then try adding the monitor.

2. Timed Out

1. Description: The DNS server was unable to resolve the request due to a timeout.
   
2. Possible Causes: This can occur if the server is overloaded, network connectivity is unstable, or there is a delay in the response from an upstream server.
   
3. Troubleshooting:
   
1. Try increasing the timeout and try again.
   
2. Use nslookup <hostname> in a command prompt from the Applications Manager server to manually test DNS resolution.
3. If the issue persists, check the network connection, DNS server configuration, and server logs for additional details.

3. Type Not Found

1. Description: The selected record type is not available on the DNS server.
   
2. Possible Causes: This may happen if the DNS server does not support the requested record type or if the record type is not configured for the specified domain.
   
3. Troubleshooting:
   
1. Choose a supported record type that is configured on the DNS server.
2. Run the command in terminal nslookup -type=<record_type> <hostname> and verify if the record type is configured in the server.
   
1. Eg - nslookup -type=AAAA apm-server
   
3. If nslookup command was successful, try adding the monitor.
4. If the available record types are not known, contact the DNS server administrator to identify the supported record types for the specified domain.

4. SERVFAIL

1. Description: The DNS server encountered an internal error while processing the request.
   
2. Possible Causes: This error may be due to server misconfiguration, network issues, or problems with upstream DNS servers.
   
3. Troubleshooting:
   
2. Use nslookup <hostname> in a command prompt from the Applications Manager server to manually test DNS resolution.
3. Check the DNS server logs for more detailed information on the error.
   
4. Investigate potential issues with server settings, network connectivity, or the upstream DNS configuration.
   
5. Check with DNS server administrator for resolving the SERVFAIL internal error.
   

5. NOTIMP

1. Description: The selected record type is not supported by the DNS server.
   
2. Possible Causes: This occurs if the DNS server does not implement or support the requested record type.
   
3. Troubleshooting:
   
1. Choose a record type that is supported by the DNS server.
   
2. Run the command in terminal nslookup -type=<record_type> <hostname> and verify if the record type is configured in the server.
   
1. Eg - nslookup -type=AAAA apm-server
3. Confirm compatibility of the requested record type with the DNS server’s configuration.
   
4. If the available record types are not known, contact the DNS server administrator to identify the supported record types for the specified domain.

6. REFUSED

1. Description: The DNS server refused the query.
   
2. Possible Causes: This may happen if the server is queried for a domain, it does not manage, or if it has been configured to restrict certain queries. It can also occur if recursion is disabled or if access permissions prevent the query from being processed.
   
3. Troubleshooting:
1. Use nslookup <hostname> in a command prompt from the Applications Manager server to manually test DNS resolution.
   
2. If nslookup was successful resolving the IP address, then try adding the monitor.
3. Verify the server’s configuration to ensure it is set up to handle the requested domain and record type.
   
4. Confirm that recursion settings and access permissions are correctly configured.
   
5. Check with DNS server administrator for troubleshooting the issue further.

7. SERVFRecord TypeIL (SERVFAIL Due to Record Type)

1. Description: The DNS server encountered a failure while processing the query (SERVFAIL), likely due to issues with the requested record type.
   
2. Possible Causes: Server misconfiguration, DNSSEC validation issues, problems with upstream server connections, or unsupported record types.
   
3. Troubleshooting:
   
1. Check the DNS server configuration.
   
2. Ensure that DNSSEC settings are correct if enabled.
   
3. Verify that the requested record type is supported by the server and consult server logs for detailed error information.
   
4. Run the command in terminal nslookup -type=<record_type> <hostname> and verify if the record type is configured in the server.
   
1. Eg - nslookup -type=AAAA apm-server
5. Check with DNS server administrator for checking the issue further.
   

8. OneElement(ANY)

1. Description: The oneElement(ANY) error appears when a DNS query is made with the ANY record type, requesting all DNS records associated with a domain. Some DNS servers are configured to limit responses to ANY queries due to performance concerns, security policies, or to protect against abuse, resulting in this error
   
2. Possible Causes: If no specific record type is selected, the default record type will be set to ANY, which could cause this error if the server does not support ANY queries
3. Troubleshooting:
   
1. Choose a record type that is supported by the DNS server and try again.
   
2. Run the command in terminal nslookup -type=<record_type> <hostname> and verify if the record type is configured in the server.
   
1. Eg - nslookup -type=AAAA apm-server
   
3. If the available record types are not known, contact the DNS server administrator to identify the supported record types for the specified domain.

9.NOTAUTH

1. Description: The NOTAUTH (Not Authorized) DNS error occurs when a DNS server refuses a query or update request because it is not authoritative for the specified zone or lacks the necessary permissions to perform the operation.
2. Possible Causes: 
   
1. Non-Authoritative Server: The DNS server being queried is not authoritative for the requested zone.
   
2. Access Restrictions: The server is configured to deny certain types of queries, either globally or for specific zones.
   
3. Incorrect Query Target: The query or update request is sent to the wrong DNS server.
   
4. Delegation Issues: Zone delegation may be improperly configured, leading the query to a non-authoritative server.
3. Troubleshooting:
   
1. Confirm that the DNS server is properly configured as authoritative for the zone.
   
2. Verify that the zone files are present and correctly loaded on the server.
   
3. Review the server’s access control lists (ACLs) and security settings to ensure they permit the requested operation.
   
4. Verify that the zone delegation is correctly configured. Check that the parent zone points to the correct authoritative servers for the subzone.
   
5. Use the below commands for troubleshooting the issue
   
1. dig <hostname> +trace - For Linux
   
2. nslookup -d2 <hostname> - For Windows
   
6. Check with DNS server administrator for checking the issue further.

10. UNRECOVERABLE Error (Data or Server Error)