Troubleshooting "Related Field has invalid lookup: icontains"

Question

Have you tried adding the __fieldname on those Lingua references in the ListinoTraduttoreAdmin search_fields, like:

class ListinoTraduttoreAdmin(admin.ModelAdmin):        
    list_display = ("traduttore", "linguaDa", "linguaA", "prezzoParola", "prezzoRiga", "scontoCat", "scontoFuzzy", "scontoRipetizioni")
    search_fields = ['traduttore__nome", "linguaDa__field1", "linguaA_field2"]

This is to (hopefully) simplify the answer.

Don't filter on a ForeignKey field itself!

---

Change this

search_fields = ['foreignkeyfield']

to this (notice TWO underscores)

search_fields = ['foreignkeyfield__name']

name represents the field-name from the table that we have a ForeignKey relationship with.

Hope this helps

Use Django's double underscore convention instead. docs foreignkeyfield__name

Make sure you are not adding any Foreignkey or ManyToManyField to your search_field directly.

class ListinoTraduttoreAdmin(admin.ModelAdmin):
    list_display = ("traduttore", "linguaDa", "linguaA", "prezzoParola", "prezzoRiga", "scontoCat", "scontoFuzzy", "scontoRipetizioni")
    search_fields = ['traduttore__nome", "linguaDa__field1", "linguaA__field2"]

Double underscore needed

class exampleAdmin(admin.ModelAdmin):
 search_field = ('yourforeignkeyname__choosefieldnameinyourforeignkey')