In Pidgin version 2.10.10 it's no longer possible to connect to a XMPP server which uses a self signed SSL certificate. So while connecting to domains with self signed SSL, we will get the error "The certificate for could not be validated. The certificate chain presented is invalid."
We can resolve this problem by upgrading the version to 2.10.11.
Also we can resolve this problem by manually downloading the ssl certificate from server. Steps for this manual configuration is given below.
Step1: Change the location to the pidgin certificate saving folder
Step2: Collect the certificate and save to a file with the name of the domains
#echo QUIT | openssl s_client -connect DOMAIN:5223 | sed -n "/BEGIN\ CERTIFICATE/,/END\ CERTIFICATE/p" > DOMAIN
Here we need to replace 'DOMAIN' with the name of the domain
Step3: Re-enable pidgin