Hi all, the title says it all pretty much. I am trying to combine time-domain linear viscoelasticity (Prony series) with user-defined anisotropic hyperelastic behaviour. Both of these properties work in Abaqus independently. When I combine them, I immediately get the following error upon job submission:

***ERROR: SYSTEM ERROR 1 IN STD_PLRDECDG

Any ideas what this means? Thanks!