The file is clearly there, but when it is opened, it shows that the resource does not exist.
As shown below:
After opening an error, the resource does not exist, and then modify the file name and it can be opened. The reason is that there is a problem with the file reference. The file reference is difficult to see. Therefore, you can create a new file and open the file that cannot be opened with other text tools. Then copy the content to the new file, delete the old file, rename the new file, and it's OK.