Having the same problem with the triode. Pretty much unconditional, no matter what I change. Tried simulating the Matsumin "starvation mode" distortion pedal. https://www.diyaudio.com/community/attachments/valve_caster_10-png.730321/ Figured it might be the 9v supply, bumped it up an varying increments all the way to 200v... convergence fails with any typical components or voltages for a circuit like this.

I also get this, for instance when adding a capacitor of sufficient value to a simple bridge rectifier when the ground is on the low side of the AC supply. It simulates fine for low capacitance, but when I increase (in a reasonable range) it fails to converge.

When I move the ground to the low side of the rectifier bridge it simulates fine, with any capacitor value.

What the hell is a 'covergence failure' anyway? Nothing in the user manual… is it a programming error code?

When I run the same circuit on my iMac, no convergence failure, but the color coding on the components is all mixed up - three are green, then one turns red. What the heck?

Is this app even supported any more?

Same error here. When the elements are highlighted in red does that mean all the smoke has been let out of it? (fried component?)

Also, is this board looked at by anyone? It's been two years since the last comment, doesn't the app creator have any ideas? Or at least acknowledge the problem (if there is one)...

ditto

Seconded -- I often run into this error, especially with transistors and diodes in the same circuit (which means all the time).