So being my first base defense event, I'm a bit confused by the interface. What exactly is the strategy here? Will we not be able to reuse the ships we use for the next node? Third fleet slot is locked?
Try this, Switch the Menu 2nd page 'Blue Button on bottomright' > Setting 【设定】> Scroll down on the right side > Recheck file 【文件检查】, if your file are corrupted, it should be restart automatically and redownload some files.
Or, are you running a lot program in the background?