Plastic Hardening Model in FLAC3d

Hi all, what is a possible reason for this Error in FLAC3D (Plastic-Hardening model: Eoed_ref is too small upon other parameters.),if I assign the stiffness parameters as described in this figure? Thanks in advance:)

From the data, you input coefficient-normally-consolidation (K0) = 1.0, which seems not common. In other words, the inputs parameters cannot reproduce this coefficient-normally-consolidation value during a virtual (internal) oedometer test simulation. Try reducing this parameter into, say, 0.8, 0.7, 0.6; or reducing stiffness-oedometer-reference, or both.