Fisher Information Matrix is Singular - Why?

[Severo III Balasbas]

Hello everyone,

I am currently using COPASI but whenever I use particle swarm to estimate the parameters of my model (mainly based on convenience kinetics), I get a warning saying that the Fisher Information Matrix is singular. I have no idea how to resolve this problem, but it would be great if someone can help me identify the cause and how to resolve it.

I don't even know where to look first: is it because the model is not structured properly? Can I ignore that message?

For anyone who would want to see it:

https://nextcloud.mpi-magdeburg.mpg.de/index.php/s/PMSgywFkFRYiZCY