diff --git a/crates/api/src/site/block.rs b/crates/api/src/site/block.rs
index be48e8ce8..7d28e43d5 100644
--- a/crates/api/src/site/block.rs
+++ b/crates/api/src/site/block.rs
@@ -19,6 +19,10 @@ pub async fn block_instance(
 ) -> Result<Json<BlockInstanceResponse>, LemmyError> {
   let instance_id = data.instance_id;
   let person_id = local_user_view.person.id;
+  if local_user_view.person.instance_id == instance_id {
+    return Err(LemmyErrorType::CantBlockLocalInstance)?;
+  }
+
   let instance_block_form = InstanceBlockForm {
     person_id,
     instance_id,
diff --git a/crates/utils/src/error.rs b/crates/utils/src/error.rs
index 34f636705..7d84dcbf6 100644
--- a/crates/utils/src/error.rs
+++ b/crates/utils/src/error.rs
@@ -227,6 +227,7 @@ pub enum LemmyErrorType {
   BanExpirationInPast,
   InvalidUnixTime,
   InvalidBotAction,
+  CantBlockLocalInstance,
   Unknown(String),
 }