If the programs that you tried to record on a tape is not loading on your Commodore 64,here is the troubleshooting.
1.Inspect the tape,is it creased? Pressure pad missing?
2.Clean the heads,capstan and the pinch roller with IPA and cotton buds.
3.Do not tick the "inverted waveform" box.It is used for transfering from tape to PC,not for recording to tapes.
4.Go to sound settings and make sure USB Pnp sound device is set as default for the playback.
5.Do not use your computer while recording.If you get any audio notifications from Facebook or messenger,it will be recorded to the tape.
6.
DOWNLOAD Recorder Justage and record it to tape.Try loading on C64.
7.Backup that not loading tape back to PC and send me the WAV file so I can investigate what is wrong with it.