gpg - decrypt generating zero byte output

Question

In Python, trying to decrypt a file using gnupg.

Using 'import gnupg'. (NOT python-gnupg).

Getting error message - (gnupg:FAILURE status emitted from gpg process: decrypt 4294967295") AND its not decrypting the file. Generating 0 byte output file.

gpg --version >> 2.2.27

Debug info/Hints -

1. After importing private key, I get fingerprint. However, gpg --list-key gives output "/root/.gnupg/pubring.gpg". gpg --list-secret-keys, does not give any output.

2. Permission issue is taken care of.

3. gpg agent is running. Getting process id for pgp gpg-agent command.

4. cs_gpg_options = ['--pinentry-mode loopback']
   gpg = gnupg.GPG(homedir='~/.gnupg', options=cs_gpg_options, verbose=True)
   

5. with open('test_encrypted.csv.gpg', 'rb') as f:
       decrypted_data = gpg.decrypt_file(
         f,
         passphrase='XXX_1234',
         output='check123.csv')
   

gpg.decrypt() has also been tried but issue persists.

Any pointers, kindly share.