MUSE spectra of all the SMGs previously detected toward the SPT2349-56 system at z = 4.304. The spectra are centered at the expected wavelength for Lyman-α line emission. The red vertical line highlights the location of the Lyman-α emission line expected from the previous [C II]- or CO-based redshift measurement (Miller et al. 2018; Hill et al. 2020). None of the SMGs are formally detected in Lyman-α emission, and only mild evidence for this line is seen in some of these spectra.