diff --git a/salt/apache/files/conf/letsencrypt.conf b/salt/apache/files/conf/letsencrypt.conf
index 6a48cf86..eff23c2b 100644
--- a/salt/apache/files/conf/letsencrypt.conf
+++ b/salt/apache/files/conf/letsencrypt.conf
@@ -1,6 +1,7 @@
 <IfModule md_module>
     MDContactEmail sysadmin@open-contracting.org
     MDCertificateAgreement accepted
+    MDCAChallenges http-01
 {%- for directive, value in salt['pillar.get']('apache:modules:mod_md', {})|items %}
     {{ directive }} {{ value }}
 {%- endfor %}