diff --git a/internal/app/app_test.go b/internal/app/app_test.go
index 61cffa3..5689100 100644
--- a/internal/app/app_test.go
+++ b/internal/app/app_test.go
@@ -12,6 +12,7 @@ import (
 	"os"
 	"os/exec"
 	"reflect"
+	"runtime"
 	"strings"
 	"sync"
 	"syscall"
@@ -437,6 +438,9 @@ func TestApp_Run_ReturnsStartError(t *testing.T) {
 // Run; the parent signals only after the SMTP port accepts a connection.
 func testRunShutsDownOnSignal(t *testing.T, sig syscall.Signal) {
 	t.Helper()
+	if runtime.GOOS == "windows" {
+		t.Skip("Windows cannot deliver SIGINT or SIGTERM to a child process")
+	}
 
 	if os.Getenv("INBOUNDPARSE_RUN_SIGNAL_CHILD") == "1" {
 		serveUntilShutdownSignal(t)
diff --git a/internal/smtp/server_test.go b/internal/smtp/server_test.go
index 87eb5db..5595d11 100644
--- a/internal/smtp/server_test.go
+++ b/internal/smtp/server_test.go
@@ -825,8 +825,9 @@ func TestSMTPServer_Start_PlainBindFailureReturns(t *testing.T) {
 	if startErr == nil {
 		t.Fatal("expected Start() to return the plain bind error")
 	}
-	if !strings.Contains(startErr.Error(), "address already in use") {
-		t.Fatalf("Start() error = %v, want address already in use", startErr)
+	msg := startErr.Error()
+	if !strings.Contains(msg, "address already in use") && !strings.Contains(msg, "Only one usage of each socket address") {
+		t.Fatalf("Start() error = %v, want a bind conflict", startErr)
 	}
 
 	ln, listenErr := net.Listen("tcp", tlsAddr)