In my app we are using RSA key, that the app generate (using android key store) on the first launch. From unknown reason, the app failed to retrieved the key from the key store
Just in case someone will run into the same problem: I've found out that Azure Active Directory library for android suffer from similar issue, and from reading the code I've saw they linked to two issues that are similar to this problem and to another issue we have. Because of that I am planing to use keystore based on p12 file, stored in the app private storage.