be more generous with time drift

src/sso_server/sso_server/auth/auth_machdb.py

@@ -63,8 +63,8 @@ class Auth(AuthBase):
             crypt.crypt(password, pwcache[username]) == pwcache[username]):
             if totp_key:
                 ok, drift = accept_totp(totp_key, otp or '', format='dec6',
-                                        period=30, forward_drift=1,
-                                        backward_drift=1)
+                                        period=30, forward_drift=2,
+                                        backward_drift=2)
                 return ok
             return True
         return False