IonicMinimize: Step failed along negative gradient direction. IonicMinimize: Probably at roundoff error limit. (Stopping)

[AndrewTaehonKim]

Dear Shankar,
Thank you very much for this incredible software. I have been using it very well for my research for surface adsorption. I am quite new to computational chemistry, so I am not quite sure how to interpret this error. Your wisdom and advise would be greatly appreciated! I have attached all of the necessary input files and .xsf file for your reference.

I am having a frequently having this error:

IonicMinimize: 	Step failed along negative gradient direction.
IonicMinimize: Probably at roundoff error limit. (Stopping)

I am not quite sure how to interpret this or if this signifies that the molecule may be at a local minimum and is more-or-less converged. I have tried perturbing the molecule by manually changing the ionic positions slightly and re-running JDFTx, but I still end up with the same error. It appears to me that the molecule is in a pretty stable adsorbed position:

Please let me know what you think may be the issue.

Google Drive: https://drive.google.com/drive/folders/1CB5EBV8hFugKRox10QmiPfns7jH7HrzR?usp=sharing
lattice.txt
output.txt
input.txt
ionpos.txt

Thank you again for everything.
Best,
Andrew Kim

[shankar1729]

Hi Andrew,

The SCF is not converging, leading to wrong forces and hence failure of the ionic minimization. Try the electronic-minimize algorithm instead, or increase the number of SCF cycles / reduce the mixing fraction etc. to get it to converge better.

Best,
Shankar