diff --git a/offlineimap/repository/IMAP.py b/offlineimap/repository/IMAP.py
index 0e1ea6e..f7651f2 100644
--- a/offlineimap/repository/IMAP.py
+++ b/offlineimap/repository/IMAP.py
@@ -309,32 +309,40 @@ class IMAPRepository(BaseRepository):
         refresh_token = self.getconf('oauth2_refresh_token', None)
         if refresh_token is None:
             refresh_token = self.localeval.eval(
-                self.getconf('oauth2_refresh_token_eval', "lambda: None")
-            ).strip("\n")
+                self.getconf('oauth2_refresh_token_eval', "None")
+            )
+            if refresh_token is not None:
+                refresh_token = refresh_token.strip("\n")
         return refresh_token
 
     def getoauth2_access_token(self):
         access_token = self.getconf('oauth2_access_token', None)
         if access_token is None:
             access_token = self.localeval.eval(
-                self.getconf('oauth2_access_token_eval', "lambda: None")
-            ).strip("\n")
+                self.getconf('oauth2_access_token_eval', "None")
+            )
+            if access_token is not None:
+                access_token = access_token.strip("\n")
         return access_token
 
     def getoauth2_client_id(self):
         client_id = self.getconf('oauth2_client_id', None)
         if client_id is None:
             client_id = self.localeval.eval(
-                self.getconf('oauth2_client_id_eval', "lambda: None")
-            ).strip("\n")
+                self.getconf('oauth2_client_id_eval', "None")
+            )
+            if client_id is not None:
+                client_id = client_id.strip("\n")
         return client_id
 
     def getoauth2_client_secret(self):
         client_secret = self.getconf('oauth2_client_secret', None)
         if client_secret is None:
             client_secret = self.localeval.eval(
-                self.getconf('oauth2_client_secret_eval', "lambda: None")
-            ).strip("\n")
+                self.getconf('oauth2_client_secret_eval', "None")
+            )
+            if client_secret is not None:
+                client_secret = client_secret.strip("\n")
         return client_secret
 
     def getpreauthtunnel(self):