diff --git a/ops/selfhost/server/nginx-crawlproof.conf b/ops/selfhost/server/nginx-crawlproof.conf
index 7ff02f3..a4d0e62 100644
--- a/ops/selfhost/server/nginx-crawlproof.conf
+++ b/ops/selfhost/server/nginx-crawlproof.conf
@@ -47,6 +47,10 @@ server {
         proxy_send_timeout    300s;
         proxy_read_timeout    300s;
         proxy_buffering       off;
+        # Supabase auth cookies overflow the default header buffer (502).
+        proxy_buffer_size       64k;
+        proxy_buffers           8 64k;
+        proxy_busy_buffers_size 128k;
     }
 }
 
@@ -86,5 +90,9 @@ server {
         proxy_send_timeout    3600s;
         proxy_read_timeout    3600s;
         proxy_buffering       off;
+        # Supabase auth cookies overflow the default header buffer (502).
+        proxy_buffer_size       64k;
+        proxy_buffers           8 64k;
+        proxy_busy_buffers_size 128k;
     }
 }