Resolving the dynamical mass tension of the massive binary 9 Sagittarii M. Fabry, C. Hawcroft, A. J. Frost, L. Mahy, P. Marchant, J.-B. Le Bouquin and H. Sana A&A, 651 (2021) A119 Published online: 29 July 2021 DOI: 10.1051/0004-6361/202140452