meshing error:the follwing faces have more than 1 external loop
 

i used the meshing model in ANSYS Fluent, but it appeared an error :"the following faces have more than 1 external loop Bodies with these types of faces are not sweepable. please edit your geometry to split these faces into faces with single exterior loop.......". but i don't know where the error is. how could i do to resolve it?

hope to get your help!