/var/www as NFS mount works fine, but protected folders do not

When mounting /var/www as an NFS share, everything works fine except »protected folders«.
I can create the protected folder in ISPConfig 3.2.11 without problem, but when trying to access it I get:
ERROR 403 - Forbidden!
You are not permitted to access the requested URL.
Please contact the webmaster with any queries.
with this error message in the log:
[Sun Sep 03 15:52:51.531955 2023] [core:crit] [pid 555992:tid 139637727110720] (13)Permission denied: [client 192.168.170.46:48824] AH00529: /var/www/clients/client0/web3/web/wasserfest/.htaccess pcfg_openfile: unable to check htaccess file, ensure it is readable and that '/var/www/clients/client0/web3/web/wasserfest/' is executable
But the permissions are correct:
total 11M
drwxr-xr-x 2 web3 client0 4,0K Sep 3 15:42 .
drwx--x--x 10 web3 client0 4,0K Sep 3 15:41 ..
-rwxr-x--x 1 web3 client0 209 Sep 3 15:41 .htaccess
-rwxr-x--x 1 web3 client0 124 Sep 3 15:41 .htpasswd
I am lost how to proceed. Anybody any idea?

 

Thanks! Indeed:
After changing the group membership as follows:
-rwxr-x--x 1 web3 www-data 266 Sep 3 16:05 /var/www/oo7.ovh/web/wasserfest/.htaccess
-rwxr-x--x 1 web3 www-data 124 Sep 3 15:41 /var/www/oo7.ovh/web/wasserfest/.htpasswd
everthings works as planned.
How persistant will this change be?

 

It looks like a bug in NFS:
cat /etc/group|grep www-data
www-data:x:33:
ispapps:x:5003:www-data
ispconfig:x:5004:www-data
client0:x:5005:www-data
www-data ist member of 4 groups only, which is far less than the RPC limit of 16.

 

Thanks. A workaround I can live with.