I applied 7 layers of gesso on a wood panel& oil painted it, the paint layers are peeling off; why?

I oil painted 4 layers on the gessoed wood panel, but the painting is separating from the panel, and away from the gesso like a rubber peels, what is

I oil painted 4 layers on the gessoed wood panel, but the painting is separating from the panel, and away from the gesso like a rubber peels, what is the cause? and what to do? Is it better to oil paint directly on un-gessoed wood panels? Thanks for your help.

or:I oil painted 4 layers on the gessoed wood panel, but the painting is separating from the panel, and away from the gesso like a rubber peels, what is the cause? and what to do? Is it better to oil paint directly on un-gessoed wood panels? Thanks for your help.

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