On May 21st, the developers behind the CryptXXX ransomware updated their code to version 3.0 in order to stop Kaspersky’s RannohDecryptor from decrypting files for free. It appears that this update has also had the unintended consequence of breaking the malware developers decryptor. For those who are affected by CryptXXX, it is advised that you do not pay the ransom as there is a good chance that you will not receive a working decryptor for those who paid the ransom.
Source: https://www.bleepingcomputer.com/news/security/cryptxxx-updated-to-version-3-0-decryptors-no-longer-work/