It doesn't seem to matter which solver my colleague selects, he gets the same message.

It was working OK, then he added some complexity and it failed, with this error. However, when he reverts the model to the earlier, originally working complexity, it continues to give this error.

Any ideas?

It is running SW2019, SP3, on a Core i7-6700k@4GHz, and the machine has 32GB RAM. It has an NVidia quadro K2200 graphics card.

Are we wasting our time with anything more complex than a UDL on a simply-supported beam, or should it work?

John