diff --git a/lib/layer/format/mvt.mjs b/lib/layer/format/mvt.mjs
index 00496675e..cbc7d2be6 100644
--- a/lib/layer/format/mvt.mjs
+++ b/lib/layer/format/mvt.mjs
@@ -3,6 +3,12 @@ export default layer => {
   // Assign default SRID if nullish.
   layer.srid ??= '3857'
 
+  // If 4326, return an error as this is not supported anymore. 
+  if (layer.srid !== '3857') {
+    console.warn(`Layer ${layer.key} must be set to use SRID 3857.`)
+    return;
+  }
+  
   // Assign empty style object if nullish.
   layer.style ??= {}