I am not sure if you are using oxTrust ( GUI of Gluu Server ) for cache refresh, most probably not because still you are not configuring it properly. :-)
>> Skipping target entries update. Destination server shema doesn't has next attributes: '[uid,sn,cn]'
There should be a space after every comma.
If you still interested to configure oxTrustCacheRefresh configuration file from cmd, here is how a proper setup looks like, here I am calling these seven attributes from backend
ldap.conf.source.attrs=uid, sn, cn, userPrincipalName, description, mail, givenName