diff --git a/pkg/accessreview/drivers/sentry.go b/pkg/accessreview/drivers/sentry.go
index 88328bb79..4b1cb21ea 100644
--- a/pkg/accessreview/drivers/sentry.go
+++ b/pkg/accessreview/drivers/sentry.go
@@ -17,6 +17,7 @@ package drivers
 import (
 	"context"
 	"encoding/json"
+	"errors"
 	"fmt"
 	"net/http"
 	"net/url"
@@ -26,6 +27,10 @@ import (
 	"go.probo.inc/probo/pkg/rfc5988"
 )
 
+// errSentryOrgNotAccessible signals a 404 scoped under an organization
+// slug; Sentry uses 404 (not 403) so this also covers revoked memberships.
+var errSentryOrgNotAccessible = errors.New("sentry organization is not accessible by this connector's token")
+
 // SentryDriver fetches organization members from Sentry via Bearer
 // token-authenticated REST API requests.
 type SentryDriver struct {
@@ -97,6 +102,10 @@ func (d *SentryDriver) ListAccounts(ctx context.Context) ([]AccountRecord, error
 	for range maxPaginationPages {
 		members, linkHeader, err := d.queryMembers(ctx, nextURL)
 		if err != nil {
+			if errors.Is(err, errSentryOrgNotAccessible) {
+				return nil, fmt.Errorf("sentry organization %q is not accessible; reconnect the connector with the correct organization: %w", orgSlug, err)
+			}
+
 			return nil, err
 		}
 
@@ -178,6 +187,10 @@ func (d *SentryDriver) queryMembers(ctx context.Context, url string) ([]sentryMe
 		_ = httpResp.Body.Close()
 	}()
 
+	if httpResp.StatusCode == http.StatusNotFound {
+		return nil, "", errSentryOrgNotAccessible
+	}
+
 	if httpResp.StatusCode < 200 || httpResp.StatusCode >= 300 {
 		return nil, "", fmt.Errorf("cannot fetch sentry members: unexpected status %d", httpResp.StatusCode)
 	}
diff --git a/pkg/accessreview/drivers/sentry_test.go b/pkg/accessreview/drivers/sentry_test.go
index 01e99d6c6..d6aa7ed4f 100644
--- a/pkg/accessreview/drivers/sentry_test.go
+++ b/pkg/accessreview/drivers/sentry_test.go
@@ -48,6 +48,27 @@ func TestSentryDriver(t *testing.T) {
 	assert.NotEmpty(t, r.Role)
 }
 
+func TestSentryDriverListAccountsStaleSlug(t *testing.T) {
+	t.Parallel()
+
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		assert.Equal(t, http.MethodGet, r.Method)
+		assert.Equal(t, "/api/0/organizations/acme-old/members", r.URL.Path)
+		w.WriteHeader(http.StatusNotFound)
+		_, _ = w.Write([]byte(`{"detail":"The requested resource does not exist"}`))
+	}))
+	defer srv.Close()
+
+	client := &http.Client{Transport: &hostRewriter{target: srv.URL}}
+
+	_, err := NewSentryDriver(client, "acme-old").ListAccounts(context.Background())
+	require.Error(t, err)
+	assert.Contains(t, err.Error(), `"acme-old"`)
+	assert.Contains(t, err.Error(), "not accessible")
+	assert.Contains(t, err.Error(), "reconnect")
+	assert.ErrorIs(t, err, errSentryOrgNotAccessible)
+}
+
 func TestSentryDriverListAccountsAutoDiscoversSlug(t *testing.T) {
 	t.Parallel()