frasermarlow on "[Theme: Avada] Mega Menu only half rendering"

The issue I am having is with Avada's Mega Menu. As I build the menu up, everything is working fine until I get to ~60 items or the 6th top-level item. At this stage, the top level items are refusing to accept the mega-menu option. When I select the two tick-boxes [Enable Fusion Mega Menu (only for main menu) & Full Width Mega Menu (overrides column width)] and save the menu, the options do not remain selected. The menu renders with the first 5 items rendering properly (as mega-menu) and the rest rendering as regular menu items.
I have played around with this for a whole day now (swapping items around, rebuilding the menu, trying to make the change directly in the database) but I can't get it to stick.
The site I am using to build is http://www.houseofhunt.com at the issue is apparent on that site as of 8/6/2016 at 6 PM EST.

Any advice?

Please contact with Avada theme developer https://theme-fusion.com/support/ .

Thanks Rinku. I went to the theme support first, but given that it is the week-end and that I have to tu this site around ASAP, I thought I would use the forum.

To their credit the folks at Theme-Fusion (makers of Avada) did respond and here is the answer I received, for the benefit of anybody else finding this thread in the future:

When your WordPress menu settings aren't being saved, it's generally due to a low limit being set for max_input_vars. You can check this in your System Status page.

For a larger menu structure, this should be increased to around 3000-4000. As this is a server setting, you'll need to contact your host about increasing this.

You can find more info on the System Status page here > https://theme-fusion.com/avada-doc/special-features/system-status-limits/