The necessary configuration differs depending on the app you are using.
If you have any communication restrictions, please make sure to allow and configure the necessary settings, and then test the connection from the actual device, app, and network.
Web Browser, Mobile Browser, Mobile App
No individual app settings are required.
In addition to configuring the proxy settings on the device or browser you are using, please make sure that the proxy server is set up to be able to connect to Teachme Biz.
Related: What URLs and ports should be allowed to access Teachme Biz?
https://help.teachme.jp/hc/en-us/articles/900005507666