After exchanging the coordinate system, the coordinate transformation leads to an error message: 'Transformation of one or multiple co-ordinates failed. Object type: Points Object key: ...'
The set coordinate system is as stated a geographic system (which means: degrees), but some coordinates exceed the maximum of +90N or +180E degrees or minimum of -90N or -180E degrees. Probably, the coordinates of the network meet a metric (projected) coordinate system. Try to find out which metric (projected) coordinate system actually is used, and set it to that, without the option 'Transform coordinates in case of changes'.