Proxy server between you and our server ( ) that intercepts SSL traffic and substitutes our certificate with its own one, which is different and will not be accepted by the IDE. It doesn't work because something between our site with its correct certificates replaces these certificates. OK, I've contacted support and they say it's a proxy issue &/or something replaces the certificate: Jetbrains,, trustedCertEntry, Zertifikat-Fingerprint I have managed to import Jetbrain's Keystore to my keystore, it now has 2 entries but still won't work: Chrome says this connection isn't safe (I've switched my distro and successfully activated Intellij, Chrome still has trust issues with that link): The support there told me to check my direct connection to ( ). Then it says 'Intellij was not able to detect your proxy configuration', although I do not have a proxy and my network settings are configured to have no proxy. JetProfile connection error: SSLHandshakeException: : : Signature length not correct: got 256 but was expecting 512 I'm trying to active Intellij IDEA (14) with my educational license under Ubuntu-gnome (15.4) getting an SSLHandshakeException: