NEB Convergence fails (EDDDAV: Call to ZHEGV failed. Return)

[mishralu]

Dear All,
In CI-NEB calculations, my middle image do not converge even two ionic iteration, it stops after 1-3 electronic steps Error EDDDAV: Call to ZHEGV failed. Returncode = 32 2 18. I have tried NEB calculations with 3, 5, 8, 12 images but all having same problem.
I have tried ALGO normal, fast, veryfast, also played with AMIX and BMIX parameters. The problem is always middle image do not converge after 1-3 electronIc convergence and error is same as I mentioned.
There is no sense of playing with potim value because even one ionic iterations is not achieved.
My system is hydrogination of CO2 on surface. I have visualized all images in all cases and images looks OK.

Any help will be highly appreciated.
Many thanks,
Dr. Abhishek Mishra

[mishralu]

correction- I mentioned- it does not converge after even two ionic iteration- but I meant to say it doesnot converge even after 1-2 electronic iterations.