How to modify the program in the face of this error reporting situation

@yeah, welcome to the Forum!

The error message is clear enough, but to help you with solving this, we need to see more of the program, in particular the declarations of the variables that are involved. You can use the </> icon to post code instead of using screenshots.

@yeah
The same upload button you used to share a screen photo as .png can be used to upload a file with file extension .txt (in case your source code still is FORTRAN), or .f90 (if it is Fortran). If the relevant source code is under an embargo (intellectual property, preparing a journal publication, etc), simplify it retaining the concept (MRE), then upload this self-sufficient example.