Permission for ISCSI disk


i installed nextcloud 18 on Ubuntu 20… And i connected iscsi disk to ubuntu and i need set nextcloud data to ISCSI disk. But when i set path to ISCSi there is error.

First that you don’t have permission for read,write… when i aproved this permission there is next error that i need set 0770 permission. After set 0770 is here this error and I don’t know how to fix it.

"Your data directory is invalid Ensure there is a file called “.ocdata” in the root of the data directory. Your data directory is not writable Permissions can usually be fixed by giving the webserver write access to the root directory. "

Could you help?