Tito leaves invitation to no avail (2,4)

I believe the answer is:

in vain

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'to no avail' is the definition.
('in vain' can be a synonym of 'to no avail')

I don't understand the remainder of the clue.

Can you help me to learn more?

(Other definitions for in vain that I've seen before include "Without effect" , "Without success or result" , "To no purpose" , "Uselessly, without success" , "Fruitlessly" .)

I've seen this clue in the Irish Times.

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