Testing file IO errors in python
The design of the readconfig() function is seriously problematic.  It makes no sense to convert caught exceptions into data, as if the file literally contained the string "FileNotFoundError" or "PermissionError".  If you don't have a good way to handle an exception, the right thing to do is let it propagate.

The readfile() function should be simpler:

def read_file(path):
    with open(path) as file:
        return file.read()


To note:


Since "read file" is two words in English, it should not be written as a compound word.
myfile could be better named.  It's a filesystem path, not a file handle.  Also, who is "me" in this case?
The 'r' mode is the default.
You don't need to call file.close() on an already closed file.  The whole point of the with block is that the file is automatically closed when exiting the block.