diff --git a/base/oauth.go b/base/oauth.go
index b640bcfc..09d911d4 100644
--- a/base/oauth.go
+++ b/base/oauth.go
@@ -24,12 +24,17 @@ func (e OAuthRequiredError) Error() string {
 }
 
 // ShouldRetryAuth reports whether err means the user's OAuth credentials are
-// permanently unusable and should be deleted. Transient token-fetch failures
-// (network, 5xx) are not treated as credential errors.
+// permanently unusable and should be deleted: invalid_grant, invalid_token,
+// a missing refresh token, or a Google Workspace Account Restricted refresh
+// failure. Transient token-fetch failures (network, 5xx) and a bare
+// access_not_configured (API not enabled on the Cloud project) are not.
 func ShouldRetryAuth(err error) bool {
 	if err == nil {
 		return false
 	}
+	if IsOAuthAccountRestricted(err) {
+		return true
+	}
 	var retr *oauth2.RetrieveError
 	if errors.As(err, &retr) {
 		switch strings.ToLower(retr.ErrorCode) {
@@ -45,6 +50,34 @@ func ShouldRetryAuth(err error) bool {
 		strings.Contains(msg, "token expired and refresh token is not set")
 }
 
+// IsOAuthAccountRestricted reports whether Google Workspace has blocked this
+// OAuth client for the user (token refresh returns access_not_configured /
+// Account Restricted). This is per-account admin policy, not a missing API on
+// the Cloud project.
+func IsOAuthAccountRestricted(err error) bool {
+	if err == nil {
+		return false
+	}
+	restricted := func(s string) bool {
+		s = strings.ToLower(s)
+		return strings.Contains(s, "account restricted") ||
+			strings.Contains(s, "servicenotallowed")
+	}
+	var retr *oauth2.RetrieveError
+	if errors.As(err, &retr) {
+		code := strings.ToLower(retr.ErrorCode)
+		body := strings.ToLower(string(retr.Body))
+		if code != "access_not_configured" && !strings.Contains(body, "access_not_configured") {
+			return false
+		}
+		return restricted(retr.ErrorDescription) ||
+			restricted(retr.ErrorURI) ||
+			restricted(body)
+	}
+	msg := strings.ToLower(err.Error())
+	return strings.Contains(msg, "access_not_configured") && restricted(msg)
+}
+
 type OAuthStorage interface {
 	GetToken(ctx context.Context, identifier string) (*oauth2.Token, error)
 	PutToken(ctx context.Context, identifier string, token *oauth2.Token) error
diff --git a/base/oauth_test.go b/base/oauth_test.go
index 0d38bede..c217ab8c 100644
--- a/base/oauth_test.go
+++ b/base/oauth_test.go
@@ -43,6 +43,24 @@ func TestShouldRetryAuth(t *testing.T) {
 	t.Run("unrelated", func(t *testing.T) {
 		require.False(t, ShouldRetryAuth(errors.New("calendar: 404 not found")))
 	})
+
+	t.Run("workspace account restricted", func(t *testing.T) {
+		err := &oauth2.RetrieveError{
+			ErrorCode:        "access_not_configured",
+			ErrorDescription: "Account Restricted",
+			ErrorURI:         "https://access.workspace.google.com/ServiceNotAllowed?application=435070579839&source=scrip",
+		}
+		require.True(t, IsOAuthAccountRestricted(err))
+		require.True(t, ShouldRetryAuth(err))
+		require.True(t, ShouldRetryAuth(fmt.Errorf("unable to renew token: %w", err)))
+		require.True(t, IsOAuthAccountRestricted(errors.New(`oauth2: "access_not_configured" "Account Restricted" "https://access.workspace.google.com/ServiceNotAllowed"`)))
+	})
+
+	t.Run("access_not_configured without restriction is not credential error", func(t *testing.T) {
+		err := &oauth2.RetrieveError{ErrorCode: "access_not_configured", ErrorDescription: "API not enabled"}
+		require.False(t, IsOAuthAccountRestricted(err))
+		require.False(t, ShouldRetryAuth(err))
+	})
 }
 
 type stubTokenSource struct {
diff --git a/gcalbot/gcalbot/account.go b/gcalbot/gcalbot/account.go
index 83723b0e..384a5325 100644
--- a/gcalbot/gcalbot/account.go
+++ b/gcalbot/gcalbot/account.go
@@ -135,6 +135,8 @@ func getCalendarService(ctx context.Context, account *Account, config *oauth2.Co
 
 const reconnectAccountMsg = "Your account '%s' needs to be reconnected. Please run `!gcal accounts connect %s` again."
 
+const restrictedAccountMsg = "Google Workspace has blocked this bot from accessing your account '%s' (an admin may have restricted the app). I disconnected it so it stops retrying. If you get access again, run `!gcal accounts connect %s`."
+
 // CalendarAuth obtains a Calendar client and recovers from invalid OAuth credentials.
 type CalendarAuth struct {
 	oauth *oauth2.Config
@@ -200,7 +202,11 @@ func (c *CalendarAuth) InvalidateIfAuthError(ctx context.Context, account *Accou
 	if delErr := c.db.DeleteAccount(ctx, account.KeybaseUsername, account.AccountNickname); delErr != nil {
 		c.debug.Errorf("failed to delete account after auth error: %v", delErr)
 	}
-	if _, sendErr := c.kbc.SendMessageByTlfName(account.KeybaseUsername, reconnectAccountMsg,
+	msg := reconnectAccountMsg
+	if base.IsOAuthAccountRestricted(err) {
+		msg = restrictedAccountMsg
+	}
+	if _, sendErr := c.kbc.SendMessageByTlfName(account.KeybaseUsername, msg,
 		account.AccountNickname, account.AccountNickname); sendErr != nil {
 		c.debug.Errorf("failed to DM user after auth error: %v", sendErr)
 	}
diff --git a/gcalbot/gcalbot/reminderscheduler/sync.go b/gcalbot/gcalbot/reminderscheduler/sync.go
index af680512..beb81b17 100644
--- a/gcalbot/gcalbot/reminderscheduler/sync.go
+++ b/gcalbot/gcalbot/reminderscheduler/sync.go
@@ -3,10 +3,12 @@ package reminderscheduler
 import (
 	"container/list"
 	"context"
+	"errors"
 	"time"
 
 	"github.com/keybase/managed-bots/gcalbot/gcalbot"
 	"google.golang.org/api/calendar/v3"
+	"google.golang.org/api/googleapi"
 )
 
 func (r *ReminderScheduler) eventSyncLoop(shutdownCh chan struct{}) error {
@@ -71,6 +73,12 @@ func (r *ReminderScheduler) syncEvents(account *gcalbot.Account, subscription *g
 			return nil
 		})
 	if err != nil {
+		var gerr *googleapi.Error
+		if errors.As(err, &gerr) && gerr.Code == 404 {
+			// Calendar was deleted or the user lost access.
+			r.Debug("calendar no longer accessible (404): %s", subscription.CalendarID)
+			err = nil
+		}
 		return
 	}
 	for _, event := range events {