diff --git a/src/mijnbib/login_handlers.py b/src/mijnbib/login_handlers.py
index 5b37814..c4e5a4f 100644
--- a/src/mijnbib/login_handlers.py
+++ b/src/mijnbib/login_handlers.py
@@ -45,6 +45,8 @@ def _log_in(self):
             _log.debug("Opening login page ... ")
             response = self._br.open(self._url, timeout=TIMEOUT)
             html_string_start_page = response.read().decode("utf-8")  # type:ignore
+            # TODO Workaround for mechanize.BrowserStateError: not viewing HTML
+            self._br._factory.is_html = True
             self._br.select_form(nr=0)
             self._br["email"] = self._username
             self._br["password"] = self._pwd
diff --git a/tests/test_mijnbibliotheek.py b/tests/test_mijnbibliotheek.py
index 588d084..5fd0304 100644
--- a/tests/test_mijnbibliotheek.py
+++ b/tests/test_mijnbibliotheek.py
@@ -19,9 +19,16 @@ def creds_config(scope="module"):
     yield dict(**config.defaults())
 
 
+class X(str):
+    pass
+
+
 class FakeMechanizeBrowser:
     def __init__(self, form_response: str) -> None:
         self._form_response = form_response.encode("utf8")
+        # trick for nested prop, from https://stackoverflow.com/a/35190607/50899
+        self._factory = X("_factory")
+        self._factory.is_html = None  # can be whatever
 
     def __setitem__(self, key, value):
         pass