Convergence error

[jcasadogp]

Hello,

I am trying to fit a series of DRM models with 2 different sets of inhibition values (2 very similar replicates) and the average of both. I don't knwo why, but it fits both replicates but returns an error when trying to fit the averaged values. The error is the following one:

Error in optim(startVec, opfct, hessian = TRUE, method = "L-BFGS-B", lower = lowerLimits,  : 
  valor de diferencia finita no finita [4]
* FAILED: 58231_UP_avg in log_ng model: Convergence failed

In the picture below you can see the 3 datasets in the points (replicates 1 and 2 in blue and average in red) and the predictions obtained from the fitted models in the lines; as you can see, the data is almost exact. I get a model for replicates but not for the average.

Does anyone know why this happens?

Thank you in advance,

Julia