Hi Tarek :)
As Michael says you must avoid sharp corners!



Let's try to mantain your shape following Michael's guidelines:
Delete mirrored surface,on top wiev hide loft sections and select contour edges of your shape joining them



Now show points of joined contour and move them where you have sharp corners



select the surface and scale just little bit larger



extrude now contour curve in both directions,so you have a blue-object that trim your surface



now you can mirror just trimmed surface and blend G2,than you can join all surfaces obtaining a solid



file attached below

M