Dear Jordi,
It appears that FAST is aborting because of an error in the mesh-mapping search for ED_L_2_AD_L_T, which is the mesh-mapping search between the ElastoDyn Line2 tower motion output mesh and the AeroDyn Line2 tower motion input mesh. FAST will trigger this error e.g. if the tower in AeroDyn starts lower than the tower in ElastoDyn or if the tower in AeroDyn ends higher than the tower in ElastoDyn.
I hope that helps.
Best regards,