diff --git a/src/Client/Grpc/GrpcDurableTaskClient.cs b/src/Client/Grpc/GrpcDurableTaskClient.cs
index 546728da..eba7b9bc 100644
--- a/src/Client/Grpc/GrpcDurableTaskClient.cs
+++ b/src/Client/Grpc/GrpcDurableTaskClient.cs
@@ -217,6 +217,7 @@ await this.sidecarClient.TerminateInstanceAsync(
     public override async Task SuspendInstanceAsync(
         string instanceId, string? reason = null, CancellationToken cancellation = default)
     {
+        Check.NotNullOrEmpty(instanceId);
         Check.NotEntity(this.options.EnableEntitySupport, instanceId);
 
         P.SuspendRequest request = new()
@@ -240,6 +241,7 @@ public override async Task SuspendInstanceAsync(
     public override async Task ResumeInstanceAsync(
         string instanceId, string? reason = null, CancellationToken cancellation = default)
     {
+        Check.NotNullOrEmpty(instanceId);
         Check.NotEntity(this.options.EnableEntitySupport, instanceId);
 
         P.ResumeRequest request = new()