Error 'The related list cannot be displayed because it is not in the current page layout' in Related List Single Component in App Builder

Check the lookup field's Field-Level Security associated with the related list. Add visibility of your profile OR the affected profile to the Lookup field. 

Steps (Classic Interface)

                  1. Standard Object: Setup | Build | Customize | <name of object>
                  2. Custom Object: Setup | Build | Create | Objects | <name of object>
                  3. Click Fields 
                  4. Look for the Lookup field and open it by clicking its name
                  5. Click the Set-Field Level Security button
                  6. Put a tick mark under 'Visible' column on the Profile needing access to the Related List 
                  7. Click Save.

Steps (Lightning Experience)

1. Navigate to Setup | Object Manager
2. Click the object affected containing the lookup field
3. Click Fields & Relationships
4. Open the Lookup Field 
5. Click Set Field-Level Security button
6. Select the Visible column on the profile that needs access to the related list 
7. Click Save.