Whenever you are browsing the internet, we recommend you only visit sites that are secure and encrypted. This keeps all information transmitting to the site private and prevents people from obtaining your sensitive information when giving out text or information in internet forms.
Always look for websites that begin with "https", especially with banking sites and online stores, or look for the padlock in the locked position.
If you have an indoor device:
If you are traveling to known good locations but are still getting this error, you may have made some changes to your indoor LTE device and it has disconnected from the internet.
Check out this article here: Huawei Indoor Antenna