Issue with MemFit and varargin

[Catsine]

Hi, I am trying to use the memtoolbox to model my data, but I run into a problem everytime I use the function MemFit (even when I use the example data). Namely, I get this error:

`Just a moment while MTB fits a model to your data...

Running 3 chains...
Error using mvnrnd (line 35)
Index exceeds the number of array elements (0).

Error in MCMC>MCMC_Chain (line 234)
movement = mvnrnd(zeros(1, length(startInfo.cur)), curCov);

Error in MCMC (line 141)
parfor c=1:numChains

Error in MemFit>MemFit_SingleData (line 188)
posteriorSamples = MCMC(data, model, 'Verbosity', verbosity-1, ...

Error in MemFit (line 117)
fit = MemFit_SingleData(data, model, verbosity);`

I tried many different solutions, but could not find a way to solve this. I am using Matlab 2019a, could it be that some functions have changed since the first publication of the toolbox?

Many thanks! :)