sql server - Datetime error querying sqlserver database via django-mssql -

i using django-mssql query sqlserver database: querying datetime value, 'conversion failed when converting date and/or time character string.'

results = sales.objects.using('eql').filter(saledate__year=2017) len(results) 

where 'saledate' datetime value - has else experienced this? (and have workaround?)