To address hostname mismatch issues:

1. **Use Correct Domain Names:**
   - Ensure the certificate is issued for the exact domain name(s) it will be used with.
   - Include both the bare domain and www subdomain if both are used.

2. **Utilize Subject Alternative Names (SANs):**
   - Use SANs to include all relevant domain names and subdomains in a single certificate.
   - This is particularly useful for services that are accessible under multiple domain names.

3. **Proper Use of Wildcard Certificates:**
   - If using wildcard certificates, ensure they are used correctly and only for appropriate subdomains.
   - Be aware of the security implications of wildcard certificates and use them judiciously.

4. **Regular Audits:**
   - Conduct regular audits of your SSL/TLS certificates to ensure they match the hostnames they're being used with.
   - This is particularly important after domain changes or service migrations.

5. **Implement Strong Domain Validation:**
   - Use Domain Validated (DV) or higher level certificates to ensure proper validation of domain ownership.

6. **Update DNS Records:**
   - Ensure DNS records are up-to-date and correctly point to the appropriate servers.

7. **Certificate Management Tools:**
   - Use certificate management tools that can detect and alert on hostname mismatches.