Surname in DS160 not getting accepted

[rrm]

Hello Friends,

I need your help again.

I am applying B2 visa for my Mom and these are her passport details:

Surname:
Given name: Name1 Name2 Name3

Since she does not have surname, from the Immihelp guide, I understand that I need to put the Given name in the Surname box while filling up DS-160 and put FNU in the Given name box. But when I tried doing that, it is not accepting three names (Name1 Name2 Name3) in the surname box, and gives this message "Please correct Surname, Surname cannot have two spaces".

What shall I do?

Thanks
RRM

[immihelp]

First Name: Name 1
Last Name: Name2 Name3

This is not risk-free and it may cause problems. They should not have such a rule. But given the circumstances, that is the best you can do.

[rrm]

First Name: Name 1
Last Name: Name2 Name3

This is not risk-free and it may cause problems. They should not have such a rule. But given the circumstances, that is the best you can do.

In passport, Given name: Name1 Name2 Name3,
Name1 is actually her Father's name
Name2 is first name
Name3 is her middle name

Shall I still go with what you recommended?

I thought, I will give the surname as: Name1 Name2Name3 and given name as FNU.

[immihelp]

You could try "Name1 Name2Name3 and given name as FNU" also.