diff --git a/src/optimise/train.jl b/src/optimise/train.jl
index 0663b9d4..12a1a272 100644
--- a/src/optimise/train.jl
+++ b/src/optimise/train.jl
@@ -43,7 +43,7 @@ function train!(loss, data, opt; cb = () -> ())
     try
       cb()
     catch ex
-      if ex isa StopException
+      if ex isa StopException()
         @info "Stop condition met"
         break
       else