Unable to modify left-side navigation menu?

[Toby McDaid]

With other SharePoint sites I've used in the modern experience, you can click 'Edit' at the bottom of your site's left-side navigation bar to edit the links.

I have one site, however, which is preventing me from doing so, despite being an owner of the site and with an Admin account for the tenant. Instead, when I click 'Edit', I am taken to a separate settings page for 'Navigation Settings'. Usually I can just edit the links without the site switching to this page.

The page I see is below. Whenever I attempt to edit the links here and click OK, I am presented with an 'Access Denied' error message saying I do not have permissions to access the resource. The same thing happens to other people with owner permissions.

Does anyone know why this is happening? Any other site I edit the links on never takes me to this page and never shows any kind of permissions denied error?

Thanks

[#2]

I have the same issue with few modern Team site Home Page as well. As soon as you click "Edit" on the Left Navigation, It takes you to https:/your tenant..../sites/YourSiteName/_layouts/15/AreaNavigationSettings.aspx. I have to re-create a new modern team site and re-edit the modern home page. If anyone out there know how to fix this issue please let us know.
Thank you in advance.
Vincent

[#3]

@Toby McDaid  Microsoft says - 

• You need to be a site owner to make changes to the navigation of a site.
• If your site has been customized by the site owner, the left-hand menu or top menu may not be available for editing.
• In SharePoint, you can only customize the left-hand menu on a team site at this time unless you are in classic mode.

Also, When you enable Modern pages on a Classic SharePoint Site, you will get the same navigation as on those Modern pages as configured in the Classic SharePoint Site. So, is it "Edit" or "Edit Links" under left navigation menu ?

[#4]

This can be caused by  enabling Server Publishing infrastructure features. 

[#5]

Yes. We have to in-activate the SharePoint Server Publishing feature.

[#6]

I mean disable the SP publishing feature.