diff --git a/Dockerfile b/Dockerfile
index 22d7d9e..6a2219b 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -37,7 +37,7 @@ ENV INBUCKET_SMTP_TIMEOUT 30s
 ENV INBUCKET_POP3_TIMEOUT 30s
 ENV INBUCKET_WEB_GREETINGFILE /config/greeting.html
 ENV INBUCKET_WEB_COOKIEAUTHKEY secret-inbucket-session-cookie-key
-ENV INBUCKET_WEB_UIDIR=ui
+ENV INBUCKET_WEB_UIDIR ui
 ENV INBUCKET_STORAGE_TYPE file
 ENV INBUCKET_STORAGE_PARAMS path:/storage
 ENV INBUCKET_STORAGE_RETENTIONPERIOD 72h