Folder in cloud but not available for Sync

Hello. Running Nextcloud 9.0.53. Planning on NC 10 soon. We are using the Owncloud clients at the moment on Windows and Mac. So here is the issue. We have a large folder with many sub folders. The root folder is owned by Admin but shared to everyone. It has been working great. We have an issue where a user on a MAC created a folder within that large folder above. They put files, etc and such in that folder. When I log in as admin and check the subfolder in the cloud and the folder is there. The subfolder she created properly has the admin as the owner inherited from the parent,. So all looks good.

However, when I go to the sync client (latest version) the folder created does not appear in the available list of folders to select from. I even tried it as the admin account (logging into sync client). So how to I get that folder to appear in the list of available folders to sync? Cron jobs are running fine, etc.

Ubuntu 16.04, PHP 7.0 and NGINX

Thanks for any assistance

Is this on external storage or the main Nextcloud storage?
If the MAC user puts files or folders in subfolders of this shared folder, are they properly synced to everybody? Can other users create files/folders in the main shared folder (like the MAC user did) and is this synced?

Thanks again for the reply. The storage location is on the nextcloud server. But it is in a separate folder /data1. I can login to Linux and see the folder there just fine from the command prompt. Permissions are the same for all files and folders. It is definitely a mystery as to why that folder does not appear to be available to sync. I will test if other users can create folders later today.

Thanks Dave

In Nextcloud 10, the a new file access control feature was implemented. You can limit the file-type and also the file size for uploads:

Well, interesting thing happened…I logged into the web interface and backed up the contents of that folder and blew it away. I then recreated the folder via the web interface and uploaded the files and everything was seen properly. And it synced. Now I had a similar issue in the past with the MAC client in regard to a file. Does not happen with the Windows clients. Odd. I will need to monitor this and test.

Thanks again