2019.3.15f1 - Can't create Keystore, please help

Hi all, I've scoured the internet for quite a few hours and I can't seem to find a fix. When trying to create a keystore I get this error:

 CommandInvokationFailure: Unable to create key in keystore. Please make sure the location and password of the keystore is correct. 
 C:/Program Files/Unity/Hub/Editor/2019.3.15f1/Editor/Data/PlaybackEngines/AndroidPlayer\OpenJDK\bin\java.exe -Xmx4096M -Dcom.android.sdkmanager.toolsdir="C:/Program Files/Unity/Hub/Editor/2019.3.15f1/Editor/Data/PlaybackEngines/AndroidPlayer\SDK\tools" -Dfile.encoding=UTF8 -jar "C:/Program Files/Unity/Hub/Editor/2019.3.15f1/Editor/Data/PlaybackEngines/AndroidPlayer/Tools\sdktools.jar" -
 
 stderr[
 Exception in thread "main" java.lang.reflect.InvocationTargetException
     at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
     at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
     at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
     at java.lang.reflect.Method.invoke(Method.java:498)
     at SDKMain.main(SDKMain.java:62)
 Caused by: java.lang.StringIndexOutOfBoundsException: String index out of range: -1
     at java.lang.String.substring(String.java:1967)
     at org.bouncycastle.asn1.x509.X509Name.<init>(Unknown Source)
     at org.bouncycastle.asn1.x509.X509Name.<init>(Unknown Source)
     at org.bouncycastle.asn1.x509.X509Name.<init>(Unknown Source)
     at org.bouncycastle.jce.X509Principal.<init>(Unknown Source)
     at UnityKeyToolGenKey.<init>(UnityKeyToolGenKey.java:78)
     at UnityKeyToolGenKey.main(UnityKeyToolGenKey.java:30)
     ... 5 more
 ]
 stdout[
 
 ]

However after this the keystore file appears in the location, and I can select it in Unity, but it never shows the alias name in the dropdown

Password is definitely correct

Anyone have some ideas?

All SDK and JDK etc are all ones installed from Unity Hub just last night