Problem character pivot point and attachment weapon

Hello everyone, excuse my English, it is not my mother tongue, I have a recent problem with my player character, I try to attach a weapon to the hand, I have created the BP of the weapon to attach it when pressing “E” and it works perfectly, but when changing the unreal mannequin for my modular character from Synty Studio, the pivot point of the character is very high and the attached weapon stays below.

when I lower my character (mesh) the weapon socket also lowers.

In the images you can see what happens so that it is better understood, I just need to lower my character without lowering the weapon socket.

I don’t know how I can fix it, and I don’t know why this happens if later in the animation it looks perfectly.

Please help.