Error Saving for new custom fields

-- HikaShop version -- : 2.6.4
-- Joomla version -- : 3.6.4

Hello
After updating hikashop I have a problem with new custom fields.
When i add a new custom field and press save I see this error:
Error
Error Saving

and when I go back to custom field list custom field is created. But when i open this new custom field Label and Column name gone and I cant edit it.
Here is a link of custom field with 0 ID :
/administrator/index.php?option=com_hikashop&ctrl=field&task=edit&cid[]=0

Hi,

Please click on the "check database" button of the HikaShop configuration and then try again.

Hi
I did it, but the error not fixed.
What can i do?

Hi,

Please provide a link to the website a backend access and a link to this thread via our contact form so that we can have a look at the problem:
www.hikashop.com/support/contact-us.html

Hi,

From what I can see the auto increment has been removed from the hikashop_field table in your database.
This can't happen during an update so I can only think that someone removed that on your end.
You need to edit the structure of the hikashop_field table in your database, and edit the field_id column and add the auto increment option:
stackoverflow.com/a/18942684/6390007

Hello

When I check A_I for field_id , I see this error:

Query error: #1075 - Incorrect table definition; there can be only one auto column and it must be defined as a key

Hi,

So that would mean that the field_id column is not the primary key of the table while it should. Please change that first.