Problem adding config file to agent job step to execute SSIS package

Greetings, have an issue adding a config file through ssms on SQL 2014. I am moving numerous 2008 R2 file based packages to a new server. I have copied about 100 packages over, scripting off the jobs from the old server, making required changes to the configs and packages to get them to run on the new 2014 server again using the file based packages not SSISDB yet. The issue I have hit with 1 package is I needed to rewrite this, i also renamed it to remove the spaces and was going to manually set up the job as I have done many times on the older servers. I added the step and browsed to the "ssis packages" folder, which would be on my machine since I was setting it up remotely and it worked fine. Then I tried to add config files which would need to be on the server and they are but the explorer window does not show any folders on the server and there are about 100. I tried remoting in to the server to do this but that doesn't work either. What am I missing here as to why I cant browse to the config files? I can simply script the job from the old server and edit the job but this should work? I tried SSMS 17 and SSMS 18 but neither would allow me to browse to the config files.

any ideas appreciated. See pic below of what I am seeing when I try to add a config file and the explorer window below shows the folder on the server.