First you will need to create a security certificate and the certificate private key.
Once you have the certificate, put it to the
c:\ProgramData\ONLYOFFICE\Data\certs\ folder, and go there:
Now run the command, converting the certificate to a
PFX (PKCS#12) file:
openssl pkcs12 -export -out onlyoffice.pfx -inkey onlyoffice.key -in onlyoffice.crt
The cerificate must be issued for the domain used by Talk. The actual domain name can be found via the http://myportal.onlyoffice.com/addons/talk/default.aspx link under the Server Name section.
The newly created certificate must be granted the proper rights:
chown onlyoffice:onlyoffice onlyoffice.pfx