diff --git a/bolt-contracts/src/contracts/BoltManager.sol b/bolt-contracts/src/contracts/BoltManager.sol
index 0ad705472..f81828c20 100644
--- a/bolt-contracts/src/contracts/BoltManager.sol
+++ b/bolt-contracts/src/contracts/BoltManager.sol
@@ -49,7 +49,9 @@ contract BoltManager is IBoltManager, OwnableUpgradeable, UUPSUpgradeable {
     uint48 public START_TIMESTAMP;
 
     modifier onlyMiddleware() {
-        require(restakingProtocols.contains(msg.sender), "BoltManager: caller is not a middleware");
+        if (!restakingProtocols.contains(msg.sender)) {
+            revert UnauthorizedMiddleware();
+        }
         _;
     }
 
diff --git a/bolt-contracts/src/interfaces/IBoltManager.sol b/bolt-contracts/src/interfaces/IBoltManager.sol
index db5097f26..1d134ca6a 100644
--- a/bolt-contracts/src/interfaces/IBoltManager.sol
+++ b/bolt-contracts/src/interfaces/IBoltManager.sol
@@ -7,6 +7,7 @@ interface IBoltManager {
     error InvalidQuery();
     error OperatorAlreadyRegistered();
     error OperatorNotRegistered();
+    error UnauthorizedMiddleware();
 
     struct Operator {
         string rpc;