HEC-RAS GIS Import Error

Doing a small river flood analysis in HEC-RAS following Andy Carters AU 2011 paper here but I kept getting this Georeference data error on GIS import into HEC-RAS

It was due to me just using the polyline drawn for the stream centreline as the basis of the alignment and it extending past the end of the surface.

I shortened the alignment and everything imports into HEC-RAS fine now.