Error on Saving quotation "server error AttributeError: 'NoneType' object has no attribute 'field type'

These post are similar, perhaps try: bench update --reset ?

https://discuss.frappe.io/t/attributeerror-nonetype-object-has-no-attribute-fieldtype-in-sales-and-purchase-invoice/28479

https://discuss.frappe.io/t/attributeerror-nonetype-object-has-no-attribute-fieldtype/52466