During development, sometimes when you open a project to install a dependency, or create a new springboot project to install some dependencies, the following errors appear inexplicably:

First check whether there is a problem with the network. If the network is normal, 99% of the problems occur in the Maven configuration of the idea. Open it   settings   -& gt; Find the location of the screenshot below and modify the following two places:

Maven home path: the installation directory of Maven
user setttings file:   Maven installation directory – & gt; conf -> Setting.xml file path
local repository: This is a customized Maven local repository after downloading Maven. Mine is in the Maven installation directory.

   After these three settings are completed, click apply, OK and refresh.