VLookup formula not working

Is the format of the cell(s) with the formulae set as text? Reformat as general.

if that;s not it...Will you please attach a SMALL sample Excel workbook (10-20 rows of data is usually enough)? Please don't attach a picture of one (no-one will want to re-type all your stuff before starting).

1. Make sure that your sample data are truly REPRESENTATIVE of your real data. The use of unrepresentative data is very frustrating and can lead to long delays in reaching a solution.

2. Make sure that your desired solution is also shown (mock up the results manually).

3. Make sure that all confidential information is removed first!!

4. Try to avoid using merged cells. They cause lots of problems!

Unfortunately the attachment icon doesn't work at the moment. So, to attach an Excel file you have to do the following: Just before posting, scroll down to Go Advanced and then scroll down to Manage Attachments. Now follow the instructions at the top of that screen.

You define name as "Data". Confirm about range. If you share sample file its more conviniant.

based on your picture
try in F2
=IFNA(INDEX($E$2:$E$10,MATCH(IFERROR(MID(A2,1,SEARCH(" ",A2)-1),A2),$D$2:$D$10,0)),"")
change references accordingly

or
with your test file:
=IFNA(INDEX($G$2:$G$10,MATCH(MID(A2,1,SEARCH(" ",A2)+1),$F$2:$F$10,0)),"")
or
if there is more than one space in the name
=IFNA(INDEX($G$2:$G$10,MATCH(TRIM(MID(A2,1,SEARCH(" ",A2)+1)),TRIM($F$2:$F$10),0)),"")
as array formula (commit by Control+Shift+Enter)

Per your file
Try this

Formula:

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Or this

Formula:

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	A	B	C	D	E	F	G
1	Name	E-mail Address	Created On			Name	E-Mail Address
2	Atest B 1203		2/11/2015 17:02			Aidan S	[email protected]
3	Aidan M 1283		2/11/2015 17:02			Alan K	[email protected]
4	Aidan S	[email protected]	8/5/2016 9:21			Alan S	[email protected]
5	Aideen A 1260		2/11/2015 17:02			Albert B	[email protected]
6	Aiden O 1335		2/11/2015 17:02			Andrew D	[email protected]
7	Alan C		2/11/2015 17:02			Andrew M	[email protected]
8	Alan K	[email protected]	11/18/2015 16:05			Anne F	[email protected]
9	Albert B	[email protected]	2/11/2015 17:02			Anne T	[email protected]
10	Andrew M 1301	[email protected]	2/11/2015 17:02			Aoife O	[email protected]

Sheet: Sheet1

Or try this into B2:

=IFERROR(VLOOKUP((LEFT(A2,(FIND(" ",A2,1)+1))),$F:$G,2,FALSE)," ")

Edit: Was a bit too slow, AlKey posted a formula like mine :-P