How do I remove the "Error: An enquiry has already been sent. Please try again in 15 minutes." function?

[Juzzyman]

Hi There

 

How do I remove the "Error: An enquiry has already been sent. Please try again in 15 minutes." function when someone sends an email? I would like the client to email me whenever they want and if they send an email followed by another one I get this error message.

 

Your help is appreciated!!

[germ]

Read this

 

Not how to remove it altogether, rather how to change the time limit.