Hi there, I am quite new to R and would like to use the arima101 forecast approach in the "forecast"-library. I tried to execute the following commands: require(forecast) var_1 <- c(372996.0) var_1 <- ts(var_1, frequency=60) var_2 <- arima(var_1,c(1,0,1),method=" CSS-ML") Error in optim(init[mask], armaCSS, method = optim.method, hessian non-finite value supplied by optim I don't really know where to find the cause of this error as I didn't call "optim" in any way. Could you give me a hint how to do it the right way? Thanks a lot in advance.