Okay so for those who are on Android using a save edit file through searching for a solution I found it this is not my method credits to lilly_cat on Reddit for this so you go to the save file location of the game then find the security_keys.text now click on it or open it it should look like this now what you have to do is delete everything but leave out the signing key and verification key and now load your save file again and it should work
To access the save file location for those who don't know yet you just have to go to main storage click android then data and find the monster girl dream game file and for those who are playing on Android 12 or above I recommend downloading a file manager to access the data since android 12 locks you out of it hope you have a great time
Bro it ain't working in my game the single key is too short