diff --git a/docs.it4i/get-started-with-it4innovations/accessing-the-clusters/graphical-user-interface/x-window-system.md b/docs.it4i/get-started-with-it4innovations/accessing-the-clusters/graphical-user-interface/x-window-system.md
index 833117661666ba6377780cfd0767bc6e308ccd03..3c6b877ca9821559517f89bf2459fd83b009fcb5 100644
--- a/docs.it4i/get-started-with-it4innovations/accessing-the-clusters/graphical-user-interface/x-window-system.md
+++ b/docs.it4i/get-started-with-it4innovations/accessing-the-clusters/graphical-user-interface/x-window-system.md
@@ -42,7 +42,7 @@ In order to display graphical user interface GUI of various software tools, you
 X Server on OS X
 ----------------
 
-Mac OS users need to install [XQuartz server](http://xquartz.org).
+Mac OS users need to install [XQuartz server](https://www.xquartz.org).
 
 X Server on Windows
 -------------------
diff --git a/docs.it4i/get-started-with-it4innovations/obtaining-login-credentials/certificates-faq.md b/docs.it4i/get-started-with-it4innovations/obtaining-login-credentials/certificates-faq.md
index e3b3e374fa6ea3a483618d76f7e019cdde3ceaa4..cced0979db40caa02b4c27afb9f1fb66ebced3db 100644
--- a/docs.it4i/get-started-with-it4innovations/obtaining-login-credentials/certificates-faq.md
+++ b/docs.it4i/get-started-with-it4innovations/obtaining-login-credentials/certificates-faq.md
@@ -25,7 +25,7 @@ Q: Which X.509 certificates are recognised by IT4Innovations?
 Q: How do I get a User Certificate that can be used with IT4Innovations?
 ------------------------------------------------------------------------
 
-To get a certificate, you must make a request to your local, IGTF approved, Certificate Authority (CA). Usually you then must visit, in person, your nearest Registration Authority (RA) to verify your affiliation and identity (photo identification is required). Usually, you will then be emailed details on how to retrieve your certificate, although procedures can vary between CAs. If you are in Europe, you can locate [your trusted CA](http://www.eugridpma.org/members/worldmap).
+To get a certificate, you must make a request to your local, IGTF approved, Certificate Authority (CA). Usually you then must visit, in person, your nearest Registration Authority (RA) to verify your affiliation and identity (photo identification is required). Usually, you will then be emailed details on how to retrieve your certificate, although procedures can vary between CAs. If you are in Europe, you can locate [your trusted CA](www.eugridpma.org/members/worldmap).
 
 In some countries certificates can also be retrieved using the TERENA Certificate Service, see the FAQ below for the link.
 
@@ -146,7 +146,7 @@ Most grid services require the use of your certificate; however, the format of y
 
 If employing the PRACE version of GSISSH-term (also a Java Web Start Application), you may use either the PEM or p12 formats. Note that this service automatically installs up-to-date PRACE CA certificates.
 
-If the grid service is UNICORE, then you bind your certificate, in either the p12 format or JKS, to UNICORE during the installation of the client on your local machine. For more information, please visit [UNICORE6 in PRACE](http://www.prace-ri.eu/UNICORE6-in-PRACE)
+If the grid service is UNICORE, then you bind your certificate, in either the p12 format or JKS, to UNICORE during the installation of the client on your local machine. For more information, please visit [UNICORE6 in PRACE](www.prace-ri.eu/UNICORE6-in-PRACE)
 
 If the grid service is part of Globus, such as GSI-SSH, GriFTP or GRAM5, then the certificates can be in either p12 or PEM format and must reside in the "$HOME/.globus" directory for Linux and Mac users or %HOMEPATH%.globus for Windows users. (Windows users will have to use the DOS command ’cmd’ to create a directory which starts with a ’.’). Further, user certificates should be named either "usercred.p12" or "usercert.pem" and "userkey.pem", and the CA certificates must be kept in a pre-specified directory as follows. For Linux and Mac users, this directory is either $HOME/.globus/certificates or /etc/grid-security/certificates. For Windows users, this directory is %HOMEPATH%.globuscertificates. (If you are using GSISSH-Term from prace-ri.eu then you do not have to create the .globus directory nor install CA certificates to use this tool alone).