<p>Solar eruptions are sudden ejections of coronal mass and magnetic fields accompanied by intense energy release. The eruptive structure does not always erupt successfully: it sometimes fails to escape the Sun after initiation. The failure of an eruption, however, provides an invaluable opportunity for improving our understanding of the intricate mechanism of eruptions. Here we present a comprehensive set of observations of a failed prominence eruption on the Sun that takes advantage of multi-viewpoint and multi-messenger imaging. Simultaneous off-limb and on-disk observations provides evidence of magnetic reconnection processes occurring at different sites during the flare. In addition to the standard flare reconnection behind the eruption, strong external reconnection occurs on the erupting flux rope, as evidenced by a wealth of signatures via multi-wavelength imaging and spectroscopy. The two reconnection processes may play contrasting roles in the acceleration of the flux rope and compete in altering the magnetic flux in the rope. As the high rate of external reconnection proceeds, the flux rope and embedded prominence decelerate noticeably and fail to erupt into the heliosphere, under strong magnetic confinement of overlying fields. Our results illustrate a well-defined physical picture for solar eruptive activities and provide insight into the lack of coronal mass ejections seen in other solar-type stars.</p>