2. If the network is perfectly fine, maybe it has something to do with the phone itself. There are some software programs that can shut down your internet connection, or maybe you accidentally pressed some switches. （
3. If you've ruled out all of the above, it may have something to do with your browser. If you are using Apple's own browser Sarafi, some aspects are not very convenient. It is recommended that you change your browser (uc browser, qq browser).
4. The last possibility is the problem of the hardware of the phone. （The last one is the hardware of the phone. (Inside the phone) For example, if you fall on it, the hardware inside the phone may not work.