Fatal error: Call to undefined function generate_get_navigation_location()

yes i can access to my dashboard but i cant customize the them bcos i get that message

Can you show me a screenshot of the "Dashboard > Updates" screen?

i just paste it

WordPress updates
Last check on April 29th 2019 at 8:00 pm. Check again

You already have the latest version of WordPress.
More information on WordPress 5.1.1.

Plugins
All plugins are updated.

Themes
All themes are updated.

Translations
All translations are up to date.

the gp plugin is the last version but the theme is not

Hmm, so you'll want to manually update.

1. Install and activate this plugin: https://wordpress.org/plugins/easy-theme-and-plugin-upgrades/
2. Download the theme: https://downloads.wordpress.org/theme/generatepress.2.2.2.zip
3. Go to "Appearance > Themes > Upload" and upload the .zip you just downloaded

ohhh jesus its ok now..thank you so much tom

Awesome! No problem - glad we got it fixed :)