This is not a setting in DNN but is done within the menu. Most themes use the DDR menu, I recommend checking out https://demo.40fingers.net/dnn-ddr-demo-skin for more info.

That said: 5 levels is quite a challenge for visitors, you might want to consider a different approach like a mega menu. 

Thank you for your reply, Mr.Tycho de Waard. But the issue is that I can't add any to the fourth-level node menus. Up to 3 levels only, I can add. The fourth-level menus are not displaying after being created and published.

 

When  you create a 5th level page and it does show up in the Tree in the Control Panel, but not in the menu on the website, then it's most likely a limitation of the Theme you are using. That's what Tycho referred to. You would need to either change the Theme or ask the creator of your theme for a change.

As Tycho and Timo have alluded to, these changes will need to be made in the theme source code. Most likely the theme you are using doesn’t support that many levels (which is a lot if these are “fly-out” submenus). There are several approaches that could be taken depending on the use case and resources.

1) You could ask the theme developer to update the theme for the desired support.

2) You could ask another theme developer to update the theme for the desired support.

3) You could try and update the theme yourself following other theme code examples (e.g., https://github.com/nvisionative/nvQuickTheme).

4) You could replace the theme with a new theme with the desired support.

5) You could work in the Information Architecture (IA) to no longer need 5 levels, and potentially lead to an improved user experience.

Also, I highly recommend upgrading to the latest version of DNN (currently 9.13.3).

To demonstrate that DNN itself supports as many levels as you want, here is what it is in the persona bar. The 'Bovenliggende pagina' is showing the parent page, in this case 5the level.

This was one of the most helpful thread of responses I've seen in a while.  DNN Community, FTW! 💪🏽

Thanks to everyone for the prompt responses. I've resolved the issue by updating the theme.

I repeat: you learn so much by just going through the recent threads from the DNN Community forum. Thanks to all of you guys, I just learned a new detail about DNN today!