surface body wont become solid after knitting

[noga roe]

hi guys
im trying to turn this surface in to solid body but its nont working
tried to use thicken, didnt work
same for boundry and loft between copy of the surface and the original one
any tips?

 

[Cadasio]

What's the error? I suspect it's self-intersecting. It's very hard to tell from that picture, are you able to share the model? Are you making it too thick for the grooves to be handled?Does it thicken one way but not the other?

This area looks like it may cause issues too - but again hard to tell without being able to inspect it properly