1. Deactivate all of your non-GP plugins – does the issue still exist? If not, activate each plugin one by one until the issue happens again. This way, you can pinpoint the problem plugin.
I’ve done and it’s the same problem
2. Turn on WP DEBUG – do any errors display in your Dashboard or on your live site?
I’ve non errors.
3. If you’re getting a white screen while Customizing or somewhere else, try increasing your memory limit.
memory limit is up.
4. Activate the core WordPress theme (TwentyFifteen) – does the issue still exist? If so, we know it’s not a GeneratePress specific issue.
When I activate the TwentyFifteen theme its shows the arrows normaly
5. Check your error_log (or ask your hosting to) – are there any big errors in there?
No relevant errors.
I’ve seen that on the android smartphone its not show an arrow rather it’s a symbol like “i can show the image”