Unable to change permissions

[Zeff]

I am the owner of an SMB share dataset and all its contents.
If I ssh in, I cannot change permissions—error message is "Operation not permitted".
On a Mac, if I attempt to change Everyone to read access it fails without displaying an error.
I can create new files and directories, but I cannot change permissions.
There is an ACL on the share:

I also have Filesystem ACLs for group@, Group, owner@, and everyone@ that all have the following settings:

I'm stumped.
Any help would be appreciated (I'm new to TrueNAS/BSD).

 

[WufiHF]

Did you also tell the permissions assignment that it should be the user xxxx and the group xxxx?
Then you must still say that he should take over the permissions recursively. Otherwise this applies only to new files.

Then you have to say that you want to apply.

Translated with DeepL

 

[Zeff]

I had done that before posting—but thanks for the suggestion.