Hello! I have used UQLab for three years, and I usually use it, but today I ran it and prompted an error:
Could not connect to the license database. Please check your connection settings (e.g. proxy).
I will be grateful if you will help me to resolve this issue.
Thanks for creating the post here. We have had a few exchanges via email, and I would like to remark on the issue for users who may encounter the same problem.
There was a recent update of the certification system in ETH where the UQLab servers are held. This triggers some incompatibility with some old versions of Matlab (e.g., 2016).
We are currently investigating this problem from our side. If it is possible, please install the latest version of Matlab to avoid it (according to my test, at least 2018a works fine.)
thanks a lot for reporting this issue, that seems to affect a handful of users on old Matlab platforms.
We ran some extensive investigation to figure out the problem, and unfortunately there is no easy solution. As @xujia mentioned, it is related to the encryption certificate chain that we use on our servers, that was updated on January 15 '22 to more recent standards.
The problem does not lie with the certificates themselves (which in principle I could try to update/modify). It lies with the fact that the certificate authority (QuoVadis Trustlink, a third-party institution that legally guarantees the validity of the encryption certificate, and hence our identity) is for some reason not recognized by Matlab 2016b and older (possibly also 2017a, but I can’t test easily). As far as I can see, there may be some workaround to this problem (hint: look for Matlab self-signed SSL certificates), but I strongly recommend against trying them, as they require root access to the main Matlab installation, and may result in potentially bigger issues.
The easiest solution is simply to upgrade to a newer version of Matlab.
The second easiest solution is to wait until the end of January, when UQLab 2.0 will be released, which will drop all licensing requirements…