The error message "The SSL certificate failed verification" in yum usually means that the SSL certificate presented by the repository server could not be verified. This could be due to various reasons, including:

1. Expired or Invalid SSL Certificate:

   • The SSL certificate of the repository server might have expired or is considered invalid by the system.

2. Misconfigured Repository:

   • The repository configuration in /etc/yum.repos.d/ might have an incorrect URL or SSL settings.

3. Incorrect System Date and Time:

   • The system's date and time settings might be incorrect. SSL certificates have expiration dates, and if your system's date is out of sync, it may fail verification.

4. Firewall or Proxy Issues:

   • Firewalls or proxies might be interfering with the SSL handshake process.

5. Package ca-certificates is Missing or Outdated:

   • The package ca-certificates contains trusted CA certificates. If it's missing or outdated, SSL verification might fail.

Here are steps to troubleshoot and potentially resolve the issue:

1. Check System Date and Time:

   • Ensure that the date and time settings on your system are correct. You can update them using the date command.

     bash

• • sudo date MMDDhhmm[[CC]YY][.ss]

• Update ca-certificates:

  • Make sure that the ca-certificates package is installed and up to date.

    bash
• • sudo yum install ca-certificates sudo update-ca-trust

• Recreate the SSL Certificate Cache:

  • Run the following command to recreate the SSL certificate cache:

    bash
• • sudo update-ca-trust force-enable sudo update-ca-trust extract

• Check Repository Configuration:

  • Verify the repository configuration files in /etc/yum.repos.d/ to ensure that the SSL settings and URLs are correct.

• Verify Firewall and Proxy Settings:

  • Ensure that your firewall or proxy settings are not blocking SSL connections. If you're behind a proxy, make sure it's properly configured.

• Temporary Disable SSL Verification:

  • As a last resort, you can temporarily disable SSL verification. However, this is not recommended for security reasons.

    Add the following line to the repository configuration file:

    arduino

6. • sslverify=false

7. Try a Different Mirror:

   • Sometimes, the mirror you're using may have a temporary issue. Try switching to a different mirror in the repository configuration file.

8. Contact Repository Provider:

   • If none of the above steps work, it's possible that there may be an issue with the repository server itself. In this case, consider reaching out to the repository provider for support.

Remember to enable SSL verification after resolving the issue to ensure secure package downloads. Disabling SSL verification should only be a temporary measure for troubleshooting purposes.