diff --git a/src/calibre/gui2/tweak_book/preview.py b/src/calibre/gui2/tweak_book/preview.py
index 8fa184b6f0..a6e54cd9a4 100644
--- a/src/calibre/gui2/tweak_book/preview.py
+++ b/src/calibre/gui2/tweak_book/preview.py
@@ -12,7 +12,7 @@ from PyQt5.Qt import (
     QApplication, QByteArray, QHBoxLayout, QIcon, QLabel, QMenu, QSize, QSizePolicy,
     QStackedLayout, Qt, QTimer, QToolBar, QUrl, QVBoxLayout, QWidget, pyqtSignal
 )
-from PyQt5.QtWebEngineCore import QWebEngineUrlSchemeHandler, QWebEngineUrlRequestJob
+from PyQt5.QtWebEngineCore import QWebEngineUrlSchemeHandler, QWebEngineUrlRequestJob, QWebEngineUrlRequestInfo
 from PyQt5.QtWebEngineWidgets import (
     QWebEnginePage, QWebEngineProfile, QWebEngineScript, QWebEngineView, QWebEngineSettings
 )
@@ -316,7 +316,7 @@ class WebPage(QWebEnginePage):
         prints('%s:%s: %s' % (source_id, linenumber, msg))
 
     def acceptNavigationRequest(self, url, req_type, is_main_frame):
-        if req_type == self.NavigationTypeReload:
+        if req_type == QWebEngineUrlRequestInfo.NavigationType.NavigationTypeReload:
             return True
         if url.scheme() in (FAKE_PROTOCOL, 'data'):
             return True
diff --git a/src/calibre/gui2/viewer/web_view.py b/src/calibre/gui2/viewer/web_view.py
index 1f2ca206c2..0409213f98 100644
--- a/src/calibre/gui2/viewer/web_view.py
+++ b/src/calibre/gui2/viewer/web_view.py
@@ -11,7 +11,7 @@ from PyQt5.Qt import (
     QT_VERSION, QApplication, QBuffer, QByteArray, QFontDatabase, QFontInfo, QPalette, QEvent,
     QHBoxLayout, QMimeData, QSize, Qt, QTimer, QUrl, QWidget, pyqtSignal, QIODevice, QLocale
 )
-from PyQt5.QtWebEngineCore import QWebEngineUrlSchemeHandler, QWebEngineUrlRequestJob
+from PyQt5.QtWebEngineCore import QWebEngineUrlSchemeHandler, QWebEngineUrlRequestJob, QWebEngineUrlRequestInfo
 from PyQt5.QtWebEngineWidgets import (
     QWebEnginePage, QWebEngineProfile, QWebEngineScript, QWebEngineView, QWebEngineSettings
 )
@@ -366,9 +366,9 @@ class WebPage(QWebEnginePage):
             pass
 
     def acceptNavigationRequest(self, url, req_type, is_main_frame):
-        if req_type == self.NavigationTypeReload:
+        if req_type == QWebEngineUrlRequestInfo.NavigationType.NavigationTypeReload:
             return True
-        if req_type == self.NavigationTypeBackForward:
+        if req_type == QWebEngineUrlRequestInfo.NavigationType.NavigationTypeBackForward:
             return True
         if url.scheme() in (FAKE_PROTOCOL, 'data'):
             return True