diff --git a/electrum/gui/qt/main_window.py b/electrum/gui/qt/main_window.py
index 7c252afb1..7ebe5e907 100644
--- a/electrum/gui/qt/main_window.py
+++ b/electrum/gui/qt/main_window.py
@@ -37,6 +37,7 @@ import base64
 from functools import partial
 import queue
 import asyncio
+from typing import Optional
 
 from PyQt5.QtGui import QPixmap, QKeySequence, QIcon, QCursor
 from PyQt5.QtCore import Qt, QRect, QStringListModel, QSize, pyqtSignal
@@ -71,6 +72,7 @@ from electrum.network import Network, TxBroadcastError, BestEffortRequestFailed
 from electrum.exchange_rate import FxThread
 from electrum.simple_config import SimpleConfig
 from electrum.logging import Logger
+from electrum.paymentrequest import PR_PAID
 
 from .exception_window import Exception_Hook
 from .amountedit import AmountEdit, BTCAmountEdit, MyLineEdit, FeerateEdit
@@ -109,9 +111,6 @@ class StatusBarButton(QPushButton):
             self.func()
 
 
-from electrum.paymentrequest import PR_PAID
-
-
 class ElectrumWindow(QMainWindow, MessageBoxMixin, Logger):
 
     payment_request_ok_signal = pyqtSignal()
@@ -141,7 +140,7 @@ class ElectrumWindow(QMainWindow, MessageBoxMixin, Logger):
         self.tray = gui_object.tray
         self.app = gui_object.app
         self.cleaned_up = False
-        self.payment_request = None
+        self.payment_request = None  # type: Optional[paymentrequest.PaymentRequest]
         self.checking_accounts = False
         self.qr_window = None
         self.not_enough_funds = False
@@ -1604,8 +1603,6 @@ class ElectrumWindow(QMainWindow, MessageBoxMixin, Logger):
         """
         pr = self.payment_request
         if pr:
-            if pr.error:
-                return True
             if pr.has_expired():
                 self.show_error(_('Payment request has expired'))
                 return True
diff --git a/electrum/paymentrequest.py b/electrum/paymentrequest.py
index 05967918d..f12fd4026 100644
--- a/electrum/paymentrequest.py
+++ b/electrum/paymentrequest.py
@@ -27,6 +27,7 @@ import sys
 import time
 import traceback
 import json
+from typing import Optional
 
 import certifi
 import urllib.parse
@@ -106,15 +107,15 @@ async def get_payment_request(url: str) -> 'PaymentRequest':
     else:
         data = None
         error = f"Unknown scheme for payment request. URL: {url}"
-    pr = PaymentRequest(data, error)
+    pr = PaymentRequest(data, error=error)
     return pr
 
 
 class PaymentRequest:
 
-    def __init__(self, data, error=None):
+    def __init__(self, data, *, error=None):
         self.raw = data
-        self.error = error
+        self.error = error  # FIXME overloaded and also used when 'verify' succeeds
         self.parse(data)
         self.requestor = None # known after verify
         self.tx = None
@@ -235,7 +236,9 @@ class PaymentRequest:
             self.error = "unknown algo"
             return False
 
-    def has_expired(self):
+    def has_expired(self) -> Optional[bool]:
+        if not hasattr(self, 'details'):
+            return None
         return self.details.expires and self.details.expires < int(time.time())
 
     def get_expiration_date(self):