diff --git a/FirebaseAuth/Sources/Backend/FIRAuthBackend.m b/FirebaseAuth/Sources/Backend/FIRAuthBackend.m
index bbd942caa11..304c7160d95 100644
--- a/FirebaseAuth/Sources/Backend/FIRAuthBackend.m
+++ b/FirebaseAuth/Sources/Backend/FIRAuthBackend.m
@@ -468,6 +468,11 @@
  */
 static NSString *const kUnsupportedFirstFactorErrorMessage = @"UNSUPPORTED_FIRST_FACTOR";
 
+/** @var kBlockingCloudFunctionErrorResponse
+ @brief This is the error message blocking Cloud Functions.
+ */
+static NSString *const kBlockingCloudFunctionErrorResponse = @"BLOCKING_FUNCTION_ERROR_RESPONSE";
+
 /** @var kEmailChangeNeedsVerificationErrorMessage
  @brief This is the error message the server will respond with if changing an unverified email.
  */
@@ -1447,6 +1452,11 @@ + (nullable NSError *)clientErrorWithServerErrorMessage:(NSString *)serverErrorM
     return [FIRAuthErrorUtils unsupportedTenantOperationError];
   }
 
+  if ([shortErrorMessage isEqualToString:kBlockingCloudFunctionErrorResponse]) {
+    return
+        [FIRAuthErrorUtils blockingCloudFunctionServerResponseWithMessage:serverDetailErrorMessage];
+  }
+
   // In this case we handle an error that might be specified in the underlying errors dictionary,
   // the error message in determined based on the @c reason key in the dictionary.
   if (errorDictionary[kErrorsKey]) {
diff --git a/FirebaseAuth/Sources/Public/FirebaseAuth/FIRAuthErrors.h b/FirebaseAuth/Sources/Public/FirebaseAuth/FIRAuthErrors.h
index 95047813572..adef87cd54b 100644
--- a/FirebaseAuth/Sources/Public/FirebaseAuth/FIRAuthErrors.h
+++ b/FirebaseAuth/Sources/Public/FirebaseAuth/FIRAuthErrors.h
@@ -413,6 +413,11 @@ typedef NS_ERROR_ENUM(FIRAuthErrorDomain, FIRAuthErrorCode){
      */
     FIRAuthErrorCodeMissingOrInvalidNonce = 17094,
 
+    /** Raised when an Cloud Function returns a blocking error. Will include a message returned from
+     * the function.
+     */
+    FIRAuthErrorCodeBlockingCloudFunctionError = 17105,
+
     /** Indicates an error for when the client identifier is missing.
      */
     FIRAuthErrorCodeMissingClientIdentifier = 17993,
diff --git a/FirebaseAuth/Sources/Utilities/FIRAuthErrorUtils.h b/FirebaseAuth/Sources/Utilities/FIRAuthErrorUtils.h
index 7bdefab7426..2c483a98168 100644
--- a/FirebaseAuth/Sources/Utilities/FIRAuthErrorUtils.h
+++ b/FirebaseAuth/Sources/Utilities/FIRAuthErrorUtils.h
@@ -605,6 +605,8 @@ NS_ASSUME_NONNULL_BEGIN
  */
 + (NSError *)unsupportedTenantOperationError;
 
++ (NSError *)blockingCloudFunctionServerResponseWithMessage:(nullable NSString *)message;
+
 @end
 
 NS_ASSUME_NONNULL_END
diff --git a/FirebaseAuth/Sources/Utilities/FIRAuthErrorUtils.m b/FirebaseAuth/Sources/Utilities/FIRAuthErrorUtils.m
index e49324918bf..3a0037aba55 100644
--- a/FirebaseAuth/Sources/Utilities/FIRAuthErrorUtils.m
+++ b/FirebaseAuth/Sources/Utilities/FIRAuthErrorUtils.m
@@ -591,6 +591,12 @@
     @"This operation is not"
      "supported in a multi-tenant context.";
 
+/** @var kFIRAuthErrorMessageBlockingCloudFunctionReturnedError
+    @brief Message for @c FIRAuthErrorCodeBlockingCloudFunctionError error code.
+ */
+static NSString *const kFIRAuthErrorMessageBlockingCloudFunctionReturnedError =
+    @"Blocking cloud function returned an error.";
+
 /** @var FIRAuthErrorDescription
     @brief The error descrioption, based on the error code.
     @remarks No default case so that we get a compiler warning if a new value was added to the enum.
@@ -755,6 +761,8 @@
       return kFIRAuthErrorMessageTenantIDMismatch;
     case FIRAuthErrorCodeUnsupportedTenantOperation:
       return kFIRAuthErrorMessageUnsupportedTenantOperation;
+    case FIRAuthErrorCodeBlockingCloudFunctionError:
+      return kFIRAuthErrorMessageBlockingCloudFunctionReturnedError;
   }
 }
 
@@ -922,6 +930,8 @@
       return @"ERROR_TENANT_ID_MISMATCH";
     case FIRAuthErrorCodeUnsupportedTenantOperation:
       return @"ERROR_UNSUPPORTED_TENANT_OPERATION";
+    case FIRAuthErrorCodeBlockingCloudFunctionError:
+      return @"ERROR_BLOCKING_CLOUD_FUNCTION_RETURNED_ERROR";
   }
 }
 
@@ -1405,6 +1415,32 @@ + (NSError *)unsupportedTenantOperationError {
   return [self errorWithCode:FIRAuthInternalErrorCodeUnsupportedTenantOperation];
 }
 
++ (NSError *)blockingCloudFunctionServerResponseWithMessage:(nullable NSString *)message {
+  if (message == nil) {
+    return [self errorWithCode:FIRAuthInternalErrorBlockingCloudFunctionError message:message];
+  }
+
+  NSString *jsonString =
+      [message stringByReplacingOccurrencesOfString:@"HTTP Cloud Function returned an error:"
+                                         withString:@""];
+  jsonString = [jsonString stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceCharacterSet]];
+
+  NSData *jsonData = [jsonString dataUsingEncoding:NSUTF8StringEncoding];
+  NSError *jsonError;
+  NSDictionary *jsonDict = [NSJSONSerialization JSONObjectWithData:jsonData
+                                                           options:0
+                                                             error:&jsonError];
+
+  if (jsonError) {
+    return [self JSONSerializationErrorWithUnderlyingError:jsonError];
+  }
+
+  NSDictionary *errorDict = jsonDict[@"error"];
+  NSString *errorMessage = errorDict[@"message"];
+
+  return [self errorWithCode:FIRAuthInternalErrorBlockingCloudFunctionError message:errorMessage];
+}
+
 @end
 
 NS_ASSUME_NONNULL_END
diff --git a/FirebaseAuth/Sources/Utilities/FIRAuthInternalErrors.h b/FirebaseAuth/Sources/Utilities/FIRAuthInternalErrors.h
index d8a29707732..96046f8a33f 100644
--- a/FirebaseAuth/Sources/Utilities/FIRAuthInternalErrors.h
+++ b/FirebaseAuth/Sources/Utilities/FIRAuthInternalErrors.h
@@ -477,6 +477,11 @@ typedef NS_ENUM(NSInteger, FIRAuthInternalErrorCode) {
 
   FIRAuthInternalErrorCodeMalformedJWT = FIRAuthPublicErrorCodeFlag | FIRAuthErrorCodeMalformedJWT,
 
+  /** Indicates that an authentication blocking cloud function returned an error.
+   */
+  FIRAuthInternalErrorBlockingCloudFunctionError = FIRAuthPublicErrorCodeFlag |
+                                                   FIRAuthErrorCodeBlockingCloudFunctionError,
+
   /** @var FIRAuthInternalErrorCodeRPCRequestEncodingError
       @brief Indicates an error encoding the RPC request.
       @remarks This is typically due to some sort of unexpected input value.