The nuclides Sn104-108, Sb106-110, Te108,109, and I111 at the expected endpoint of the astrophysical rp process have been produced in Ni58+Ninat fusion-evaporation reactions at IGISOL and their mass values were precisely measured with the JYFLTRAP Penning trap mass spectrometer. For Sb106, Sb108, and Sb110 these are the first direct experimental mass results obtained. The related one-proton separation energies have been derived and the value for Sb106, Sp=424(8)keV, shows that the branching into the closed SnSbTe cycle in the astrophysical rp process is weaker than expected.