Articles on: SSL Certificates

Troubleshooting Common Let's Encrypt Issues

Troubleshooting Common Let's Encrypt Issues at
Let's Encrypt is a free, open and automated certificate authority that provides SSL/TLS certificates. While it is a great service, users can sometimes run into issues when trying to obtain or renew certificates. Here are some common problems and solutions:
Unable to Obtain Initial Certificate
• Make sure your domain's DNS is pointing to the correct server IP
• Check that ports 80 and 443 are open for inbound connections
• Verify that your server software is configured properly to use Let's Encrypt
Certificate Renewal Failure
• Let's Encrypt requires the ability to perform HTTP validation on your domain
• Ensure that no firewall, proxy or content filter is blocking Let's Encrypt's validation request
• Check that the renewal process is automated and running without errors
Rate Limiting
• Let's Encrypt limits the number of failed validation attempts to avoid abuse
• If you hit the rate limit, you may have to wait a week or two before retrying
• Use the --renew-by-default flag when running certbot to combine obtaining and renewing
Expired Certificates
• Let's Encrypt certificates are valid for 90 days
• Set up a cron job or scheduled task to automatically renew 30 days before expiration
• Monitor renewal logs for any errors that need to be addressed
Mixed Content Warnings
• This occurs when some resources on a page are loaded insecurely over HTTP
• Ensure all resources (CSS, JavaScript, images, etc.) are referenced with HTTPS links
• Use a tool like SSL Labs or WhyNoPadLock to identify mixed content
At, we recommend using Let's Encrypt for secure SSL/TLS on your websites. Following best practices and monitoring the automated renewal process can help avoid most common issues.

Updated on: 08/05/2024

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