# Renew existing certs failing - tried --renew-by-default as well as force-renewal **URL:** \ **Category:** Help\ **Created:** [January 11, 2018, 5:44pm UTC](https://community.letsencrypt.org/t/renew-existing-certs-failing-tried-renew-by-default-as-well-as-force-renewal/50161 "2018-01-11T17:44:31Z")\ **Posts on this page:** 1\ **Showing post:** 2
**Author:** ![mnordhoff](https://sea3.discourse-cdn.com/letsencrypt/user_avatar/community.letsencrypt.org/mnordhoff/32/22583_2.png) [@mnordhoff](https://community.letsencrypt.org/u/mnordhoff)\ **Post date:** [January 11, 2018, 5:53pm UTC](https://community.letsencrypt.org/t/renew-existing-certs-failing-tried-renew-by-default-as-well-as-force-renewal/50161/2 "2018-01-11T17:53:22Z")
TLS-SNI-01 validation, used by the Apache plugin, is currently disabled by Let's Encrypt for security reasons. It may require a little setup, but you can use HTTP-01 validation with the Apache installer. > [@Solution: Client with the currently selected authenticator does not support any combination of challenges that will satisfy the CA](https://community.letsencrypt.org/t/solution-client-with-the-currently-selected-authenticator-does-not-support-any-combination-of-challenges-that-will-satisfy-the-ca/49983): > > I… Version 0.4.1 is pretty old. I don't remember exactly, but I think the Python dialog error thing is a bug with displaying errors that was fixed in a more recent version of Certbot. `--renew-by-default` was renamed to `--force-renewal`. They're equivalent. You should almost never need to use them, since they can cause unnecessary and excessive renewals. --- _[View the full topic](https://community.letsencrypt.org/t/renew-existing-certs-failing-tried-renew-by-default-as-well-as-force-renewal/50161)._