diff --git a/container-config/nginx/sites/kelder.zeus.ugent.be.conf b/container-config/nginx/sites/kelder.zeus.ugent.be.conf
index 790b934..1d0abb3 100644
--- a/container-config/nginx/sites/kelder.zeus.ugent.be.conf
+++ b/container-config/nginx/sites/kelder.zeus.ugent.be.conf
@@ -54,6 +54,8 @@ server {
         proxy_set_header X-Forwarded-Host $host;
         proxy_set_header X-Forwarded-Server $host;
         proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
+        proxy_set_header Upgrade $http_upgrade;
+        proxy_set_header Connection "upgrade";
         proxy_http_version 1.1;
         proxy_set_header Host $host;
         proxy_pass http://10.0.0.11:5000/socket.io/;