diff --git a/docker/Dockerfile b/docker/Dockerfile
index 27261e8..3c0e3dc 100644
--- a/docker/Dockerfile
+++ b/docker/Dockerfile
@@ -27,6 +27,7 @@
 # setup
 RUN apk update
 RUN apk add ca-certificates wget su-exec git
+RUN update-ca-certificates
 
 # get gitbucket
 RUN wget https://github.com/gitbucket/gitbucket/releases/download/4.33.0/gitbucket.war -O $GITBUCKET_HOME/latest.war