diff --git a/Dockerfile b/Dockerfile
index 9b64b2a..cd27a56 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -13,7 +13,7 @@ RUN \
   cd build && \
   git clone https://github.com/NLnetLabs/unbound.git && \
   cd unbound && \
-  ./configure --with-libsodium --with-libnghttp2 --with-libevent --enable-sha2 --enable-dnscrypt ---prefix /opt/unbound && \
+  ./configure --with-libsodium --with-libnghttp2 --with-libevent --enable-sha2 --enable-dnscrypt --prefix /opt/unbound && \
   make && \
   make install