My entity is not solid to players and I don't know why

My entity is not solid to players and I don’t know why;
[lua]

function ENT:Initialize()

self:SetModel(  "models/props_combine/combine_mortar01b.mdl" )      
self:PhysicsInit( SOLID_VPHYSICS )
self:SetMoveType( MOVETYPE_VPHYSICS )
self:SetSolid( SOLID_VPHYSICS )


--self:SetCollisionGroup( COLLISION_GROUP_NONE )

local phys = self:GetPhysicsObject()
if (phys:IsValid()) then          
   	phys:SetMass( 2000 )   
    phys:Wake()  
end  

end
[/lua]

other things collide with it but players can just walk through it?

maybe where it says

// Don’t collide with the player
self:SetCollisionGroup( COLLISION_GROUP_NONE )

Did you even read the code that you must have copied from somewhere?

This line should’ve given it away:
[lua]
// Don’t collide with the player
[/lua]

Oops, I have that line commented out but I accidentally deleted the – when I posted it