Convergence not achieve with SDM

[Wang Fengqiuyu]

Hi everyone,

I'm a postgraduate student in uni and a beginner with Stata. I'm working on exploring the specific factors of carbon emissions.
My data has 256 groups and Panel length is 20. I already set a balanced panel and standardized spatial weight matrix ready and tested Moran's I, LM, Huasman, where results show the sdm with time and spatial fix effect would be match the data.
But Stata reminds:
convergence not achieved
Computing marginal effects standard errors using MC simulation...
Also, my core variation doesn't show significance, while it works with ols or random effect model.
Btw, I saw some use 'from(,copy)' to make it works by adjusting the starting value(?). I'm just confused with how to solve it or what can do with original data or anything wrong with my flow. Any suggestion?

Thanks very much!

[Wang Fengqiuyu]

Another question: Is there anyway if I add some variables which don't change by time like city grade, topography in spatial panel models?