  At the Cooler Synchrotron COSY/J\"ulich spin correlation parameters in
elastic proton-proton (pp) scattering have been measured with a 2.11 GeV
polarized proton beam and a polarized hydrogen atomic beam target. We report
results for A$_{NN}$, A$_{SS}$, and A_${SL}$ for c.m. scattering angles between
30$^o$ and 90$^o$. Our data on A$_{SS}$ -- the first measurement of this
observable above 800 MeV -- clearly disagrees with predictions of available of
pp scattering phase shift solutions while A$_{NN}$ and A_${SL}$ are reproduced
reasonably well. We show that in the direct reconstruction of the scattering
amplitudes from the body of available pp elastic scattering data at 2.1 GeV the
number of possible solutions is considerably reduced.
