1. Network problem: If the network is unstable, some software packages may be lost during the download process. The solution is to reconnect to a stable network and try to download WeChat again.

2. The software version does not match the mobile phone system: the downloaded WeChat version may not support the mobile phone system of vivoX7Plus. The solution is to go to WeChat official website and download the appropriate WeChat version according to the mobile phone operating system or mobile phone model.

3. Mobile phone memory is insufficient: If the mobile phone memory is insufficient, the software download may fail. The solution is to delete files or software that are not commonly used on the mobile phone, free up storage space, and then try to download WeChat again.

4. Insufficient cache of mobile browser: If the cache of mobile browser is insufficient, the download may also fail. The solution is to clear the cache of the mobile browser, and then try downloading WeChat again.

5. Inconsistent software version signatures: If the old version of WeChat is installed on the device, the signatures may be inconsistent. The solution is to uninstall the old version of WeChat first. If it is uninstalled, but the signature is still inconsistent, you need to go to file management to delete the remaining files, and then try to install the new version of WeChat.

6. The preferred installation location is set incorrectly: some software is incompatible with the Android version: due to the long development time of the software, it may be incompatible with the Android version of the current device. The solution is to try to download other similar software to use. Please install in the system space. If the settings are incorrect, the installation may fail.