SRSPlus module requires GnuPG public key authentication.
You must generate GnuPG keys, send a public key to SRSPlus, import SRSPlus key and sign it.
For detailed instructions, check SRSPlus Manual
Once you have all keys in one folder(by default, it is usually /home/user/.gnupg/), you must specify this folder in GPG keys directory setting on SRSPLus configuration page.
This folder must be readable by your webserver user(usually nobody or apache). If it is not, you can copy all GnuPG files to another directory, for example EPP-DRS etc folder.
Path to GPG is a path to GnuPG command-line tool.
To quickly check either you did everything right, issue a following command in shell:
/path/to/gpg --list-keys --homedir=/path/to/directory
Where /path/to/directory is the same as GPG keys directory, and /path/to/gpg is the same as Path to GPG.
If you see both keys, yours and SRSPlus, it should work.
gpg binary tool must be executable by your webserver user.
You can fix this by issuing the following code in shell:
chmod +rx /path/to/gpg
Host field must be testsrs.srsplus.com for now.
Save the form and use Test module link on modules list page. If module passed configuration, proceed to next step.