Hi Alok,
I am afraid I am not able to reproduce this issue. I have attached a sample which displays the X axis labels in the format "dd/MM/yyyy hh:mm:ss tt". Could you please try running the same at your end and send me back the modified sample if still the problem exists? Also please let me know about the current version of Essential Studio you are using.
F44624.zip
Thanks for your continued interest in Syncfusion products.
Regards,
Geetha