PenciDesign replied
Hi,
Seem you didn't check documentation for Soledad theme. We've said about this here
You didn't create a menu for your AMP pages WITHOUT use category mega menu.
Note that: AMP pages doesn't supports display category mega menu, so, please go to Appearance > Menus > create a new menu for your AMP ( which don't use category mega menu ) > scroll down and check to "AMP Menu".
Best Regards,
PenciDesign