During development by using CodeOnTime, i see this weird issue. I suddenly receive error on my homepage, and when i check my app generator it show nothing in my pages & controller list.. (refer image i attach below).
Error on homepage
Error on App generator
When i post a ticket, the help-desk suggest me to restart (of course already try before ask them, and not work at all). The other way suggest is copy from backup file (unacceptable suggestion for me). Then i am start looking on the code from visual studio. I find out that Home.aspx (can be found inside folder Pages >> Home.aspx) got missing contentPlaceHolder. The highlighted code in below image is miss from my page. I copy from another project the line of code, and re-run the app generator. So far it work as well as before.