Dear thiyagartr,
it is not clear from your question if you have already read ATENA Troubleshooting, 2.2.12 How can I model a pull-out experiment? and 2.4.6 Floating point problems - Division by zero, Loss of >7 digits on the matrix diagonal, CCFEModelExc: CCPardiso solver error: zero pivot, Warning: Sign of diagonal changed when reducing equation, Floating point exception: Multiple floating points traps, Zero or negative jacobian, InvertA: zero determinant, CCMaterials Extended AExc: CC5ParamYield F: project_stress_on_f_division by zero, and similar.
You might also be interested in 2.4.2 I get the message "The execution is killed due to violation of stop iteration criteria", what does it mean?, 2.1.19 Problems reaching convergence and understanding ATENA convergence parameters, and 2.2.22 How to detect a structural collapse or ultimate load capacity.
If you can not solve the problems, please follow Troubleshooting, 2.1.1 to send us your model etc.
Regards.