Forum Discussion

Michael_Feliciano's avatar
Feb 19, 2021

F5: SSL certificate renewal problem

Hi to F5 DevCentral,


The SSL certificate (configured in our F5 load balancer) of one of our F5-hosted websites will be expiring soon.


After I configured a new SSL certificate in F5 for that website, browsing the website (using Google Chrome) displays the following error message:


This site can't provide a secure connection.


<the website's domain name> uses an unsupported protocol.




Does this mean that something is wrong with the new SSL certificate?



Michael Feliciano

8 Replies

  • Hi,


    This message indicates that the SSL version or the Cipher list supported by the F5 and its peer (the client) doesn't match.

    You should do a tcpdump on the client or on the F5 system to check the ssl handshake. You may see that there is no matching ciphers between the browser and the VS.



  • It turned out that the F5-hosted website had some existing configurations in a Palo Alto firewall. (i.e. an SSL certificate, and a decryption rule) 


    Browsing the website finally worked, after I used its new SSL certificate to update the relevant configurations in both the Palo Alto firewall and the F5 load balancer.

  • This issue usually involves a problem with your web browser or your site’s SSL certificate. The browser’s telling you that because it’s trying to tell you there’s a problem with the certificate the website is using for HTTPS, so “this site can't provide a secure connection”. In all cases the end-to-end encryption is still going to work just because HTTPS can’t function without it. There is no definite guide for managing this error.

    Two possible options to get rid of this issue

    1. Use Self Sign certificate
    2. Remove domain security policy:

    Steps for Chrome :

    • Go to : chrome://net-internals/#hsts
    • Query HSTS/PKP domain for localhost
    • Use Delete domain security policies option to delete configuration for localhost

    This error is because of the following problems:

    • Invalid SSL or SSL is untrusted (self-signed)
    • SSL Not installed properly
    • Old Technology or SSL/TLS version for encryption