How to convert file to keystore format

I am doing a react-native application. The issue is, the previous keystore is in .txt format. How can I change it into .keystore file?

I already tried these

• changing the file format manually
• using Android studio to re-create the keystore
• using this command keytool -importcert -file ***.keystore.txt -keystore ***.keystore

I tried to use the original file on the AppCenter, but I got

I tried resaving the file as .keystore, but I got

Is there any other way?

Thank you in advance.

Please try with following "keytool -importkeystore -srckeystore current_keystore.txt -destkeystore new_keystore.keystore -deststoretype pkcs12"