I did upgrade my Kaltura Server from 14.0.0 to 15.1.0. The upgrade seems to went trough fine, but if I run the kaltlog command I I get an exception and a permission error:
/opt/kaltura/log/batch/validatelivemediaservers-0-2019-07-04.err.log <== PHP Fatal error: Uncaught exception 'KalturaClientException' with message 'failed to unserialize server result PHP Class map could not be loaded' in /opt/kaltura/app/batch/client/KalturaClientBase.php:401 Stack trace: #0 /opt/kaltura/app/batch/client/KalturaClient.php(2341): KalturaClientBase->doQueue() -- thrown in /opt/kaltura/app/batch/client/KalturaClientBase.php on line 401 PHP Warning: file_get_contents(/opt/kaltura/app/cache//batch/classMap.cache): failed to open stream: Permission denied in /opt/kaltura/app/infra/KAutoloader.php on line 415 PHP Class map could not be loaded from path [/opt/kaltura/app/cache//batch/classMap.cache] file permissions 
Can someone help me how I can fix this errors?
Thanks in advance,