Problems with rights with external storage

I’m trying to install an external storage. But somehow I cannot have access to my external storage and I cannot figure out what’s wrong.

I have a hard disk with 3 partitions. One of them is for the backup and this is working just fine.

Another partition that I’m trying to make it available for external storage. I can see the drive at /media/guy/DataDisk so I followed the instruction on how to set the rights and did this;

guy@pi5:~ $ sudo chown -R 33:0 /media/guy/DataDisk
guy@pi5:~ $ sudo chmod -R 750 /media/guy/DataDisk

In the config for external storage, I entered:

the red exclamation mark tells me that it is wrong. But if I enter the path as;

/media/guy

then it accept it, but I cannot use it in the user setting.

What is wrong?

You can check the permissions with:

sudo -u www-data ls -lisa /media/guy/DataDisk
Should show you the file index.

If you still have an error, can you show us the output of
ls -lisa /media/guy