Have you tried resetting your router? There should be a pinhole near to the power button. You should use a pin, or a paper clip, and keep it inserted for 10 seconds. This will cause the router to re-set to factory conditions, including all configurations. If you changed the original settings relating to how to get into your router admin pages they will also need re-setting.
Huawei Mate 20 Pro review: In-depth hands-on