diff --git a/internal/adapter/out/postgres/tickets.go b/internal/adapter/out/postgres/tickets.go
index 3e2339f..386a046 100644
--- a/internal/adapter/out/postgres/tickets.go
+++ b/internal/adapter/out/postgres/tickets.go
@@ -6,6 +6,7 @@ import (
 	"fmt"
 
 	"github.com/jackc/pgx/v5"
+	"github.com/jackc/pgx/v5/pgconn"
 
 	"github.com/dihemoe/alisten/internal/adapter/out/postgres/internal/query"
 	"github.com/dihemoe/alisten/internal/app/port"
@@ -30,7 +31,7 @@ func (s *Store) CreateTicket(ctx context.Context, t port.NewTicket) error {
 		return q.CreateTicket(ctx, query.CreateTicketParams{TokenHash: t.TokenHash, RoomID: t.RoomID, MemberID: t.MemberID, SessionTokenHash: t.SessionTokenHash})
 	})
 	if err != nil {
-		return fmt.Errorf("签发房间 %s 的票据：%w", t.RoomID, err)
+		return fmt.Errorf("签发房间 %s 的票据：%w", t.RoomID, sessionError(err))
 	}
 	return nil
 }
@@ -50,3 +51,13 @@ func (s *Store) TicketHolder(ctx context.Context, tokenHash []byte) (port.Ticket
 		SessionTokenHash: row.SessionTokenHash,
 	}, nil
 }
+
+const foreignKeyViolation = "23503"
+
+func sessionError(err error) error {
+	var pgErr *pgconn.PgError
+	if errors.As(err, &pgErr) && pgErr.Code == foreignKeyViolation && pgErr.ConstraintName == "room_tickets_session_token_hash_fkey" {
+		return port.ErrSessionNotFound
+	}
+	return err
+}
diff --git a/internal/adapter/out/postgres/tickets_test.go b/internal/adapter/out/postgres/tickets_test.go
index ed321bb..3a18e09 100644
--- a/internal/adapter/out/postgres/tickets_test.go
+++ b/internal/adapter/out/postgres/tickets_test.go
@@ -39,6 +39,20 @@ func TestTicketHolder(t *testing.T) {
 	}
 }
 
+func TestCreateTicketRejectsDeletedSession(t *testing.T) {
+	store, _ := newStore(t)
+	alice := createMember(t, store, "alice", "甲")
+	id := createRoom(t, store, port.NewRoom{Kind: room.Ephemeral, Name: "临时"})
+	if err := store.DeleteSession(t.Context(), tokenHash("alice")); err != nil {
+		t.Fatal(err)
+	}
+
+	err := store.CreateTicket(t.Context(), port.NewTicket{TokenHash: tokenHash("t1"), RoomID: id, MemberID: alice.ID, SessionTokenHash: tokenHash("alice")})
+	if !errors.Is(err, port.ErrSessionNotFound) {
+		t.Errorf("会话已经删除时 CreateTicket = %v，期望 ErrSessionNotFound", err)
+	}
+}
+
 func TestTicketsBelongToSessions(t *testing.T) {
 	store, _ := newStore(t)
 	alice := createMember(t, store, "alice-1", "甲")
diff --git a/internal/app/identity/identity.go b/internal/app/identity/identity.go
index ed97ad4..19b0fbf 100644
--- a/internal/app/identity/identity.go
+++ b/internal/app/identity/identity.go
@@ -96,6 +96,10 @@ func (s *Service) IssueTicket(ctx context.Context, memberID, memberToken, roomID
 		// 刚才是按旧密码校验的；客户端重新输入密码后，按新密码校验。
 		return "", ErrWrongPassword
 	}
+	if errors.Is(err, port.ErrSessionNotFound) {
+		// 会话在鉴权之后被删除（例如另一台设备退出了其他设备），此时成员 token 确实已经失效。
+		return "", ErrInvalidMemberToken
+	}
 	if err != nil {
 		return "", err
 	}
diff --git a/internal/app/identity/identity_test.go b/internal/app/identity/identity_test.go
index d97a1d0..4cc631e 100644
--- a/internal/app/identity/identity_test.go
+++ b/internal/app/identity/identity_test.go
@@ -157,6 +157,19 @@ func TestTicketBelongsToIssuingSession(t *testing.T) {
 	}
 }
 
+func TestIssueTicketRejectsDeletedSession(t *testing.T) {
+	s, store := newService(t)
+	alice := createMember(t, s)
+	id := createRoom(t, store, "")
+	if err := store.DeleteSession(t.Context(), hashSecret(alice.MemberToken)); err != nil {
+		t.Fatal(err)
+	}
+
+	if _, err := s.IssueTicket(t.Context(), alice.Member.ID, alice.MemberToken, id, ""); !errors.Is(err, ErrInvalidMemberToken) {
+		t.Errorf("会话在签发之前被删除，错误 = %v，期望 ErrInvalidMemberToken", err)
+	}
+}
+
 type loggedSubscriptions struct {
 	port.Bus
 	logger *slog.Logger
diff --git a/internal/app/port/porttest/store.go b/internal/app/port/porttest/store.go
index e0800e7..f17371b 100644
--- a/internal/app/port/porttest/store.go
+++ b/internal/app/port/porttest/store.go
@@ -257,7 +257,7 @@ func (s *Store) CreateTicket(_ context.Context, t port.NewTicket) error {
 		return errors.New("成员不存在")
 	}
 	if _, ok := s.sessions[string(t.SessionTokenHash)]; t.SessionTokenHash != nil && !ok {
-		return errors.New("会话不存在")
+		return port.ErrSessionNotFound
 	}
 	if _, ok := s.tickets[string(t.TokenHash)]; ok {
 		return errors.New("票据哈希重复")
diff --git a/internal/app/port/ticket.go b/internal/app/port/ticket.go
index 11f62f7..b1e1ef6 100644
--- a/internal/app/port/ticket.go
+++ b/internal/app/port/ticket.go
@@ -34,7 +34,7 @@ type TicketHolder struct {
 
 type Tickets interface {
 	// 房间的密码哈希已经不是 t.PasswordHash 时返回 ErrPasswordChanged：密码在校验之后被修改过，
-	// 设置或修改密码时的作废已经执行，此时签发的票据不会再被作废。
+	// 设置或修改密码时的作废已经执行，此时签发的票据不会再被作废。t.SessionTokenHash 的会话已经不存在时返回 ErrSessionNotFound。
 	CreateTicket(ctx context.Context, t NewTicket) error
 	TicketHolder(ctx context.Context, tokenHash []byte) (TicketHolder, error)
 }