The code has nothing to do with it. So long as you have already added the connection to your address book and can see it online, you should be able to authorization.
From the error message we can say that something breaks the authorization routine midway. First of all please make sure that you update Viewer and Host to the most recent version (18.104.22.168 as of this writing).
The address book size doesn't really matter unless you have hundreds of thousands of Hosts in it really. I recommend that you close the Viewer and delete the Viewer configuration file (config_4.xml) which you may find in the %appdata%\Remote Utilities Files\ folder. This may fix the problem.
Conrad Sallian, Thanks again For the resolution. That did work for us.
But we have another question to ask :)
We have a pro licence with RUT & Viewer is installed on one location with 50+ Client addresses added in it. However sometimes we required to access the clients on other location So can we install RutViewer on 2nd system & use the same licence in there because the required clients already added in it.
Simple version : Can we use the same licence in 2 different systems to access the clients quickly?
Our licensing is per concurrent tech. Therefore, with a 1-tech license only one person can work at a time from a Viewer machine. If there are 2 techs who are supposed to work simultaneously, then you'll need a 2-tech license.
We have created a single click msi file package very long ago (Jan-2018). which was working fine for us. But now we realized that it is not sending all the emails to inbox and missing almost 90% of the mails. We have updated the viewer to the latest but kept the msi file as same old file. Also we were white-listed ourselves on your site long ago. Please help.
Let me know if we need to open another ticket for this particular issue. Or if you need the file to test.
We will be happy to help. You are a commercial license user, right? Could you please send us your license key to firstname.lastname@example.org along with email address that you use for sending Host emails, and we will check that.