Hi everybody,

I am lecturing an introductory course in time-series econometrics and, as usual, I use GRETL to make several empirical applications and a few simulations. The problem is that one of my students has a mac computer (I use windows); she had no problem with the installation of GRETL, but she cannot install neither X-13 ARIMA nor TRAMO-SEATS and therefore is unable to seasonally adjust any time series. The OS in her computer is macOS Catalina version 10.15.1 I tried to help her; I opened the console and wrote: "pkg install x13as-mac64.tar.gz" (and also "pkg install tramo-seats-mac64.tar.gz") but the following error appears:

"? pkg install x13as-mac64.tar.gz

cURL error 60 (SSL peer certificate or SSH remote key was not OK)"

I am completely clueless about what this means, so any help will be highly appreciated.