Navigation probs on phones and tablets only

Site URL: https://www.thenutrientteamsprotocol.com/

On my site I have two main parts ie.  1. About 5 pages which the public can see and 2. The vast majority of it (17 pages) that can only be accessed via the Bronze members area. Each has its separate navigation section in the header. That works fine from a laptop, but has a problem from phones and tablets. On those systems you click the large ‘+’ symbol, top right. The public one works fine until you go into the members area and then it disappears and you only get the members area navigation. Even if you return to the public area, you still only get the members area navigation. If you leave the site and come back, there’s still no navigation except for the members area navigation even in the public area.

I’ve added a temporary fix by adding buttons from the missing menu into the footer.

No problems at all with this on my laptop.

I’m just about to launch my site and would appreciate ideas on what’s gone wrong.

Also can the size of lettering in the navigation on phones and tablets be reduced without changing anything as seen on laptops?

TIA

Cheers, Mike

PS. Temporary site password is A265YzB7