timemachine doesn't start or send errors
Time machine doesn’t want to back up part of one disk to another disk, but your screen shot seems to show that. To be sure, I would confirm you are not just splitting up one drive and have two devices to set this up.

It might be possible to convince Time Machine from the command line to backup, so if you’re up for that, here are the two commands I would use to get you started:

diskutil list


And then

tmutil destinationinfo 


Based on your specific naming, you might be able to add your drive - being careful with characters like ( and ) - I would probably make your backup volume just “backup” without any punctuation like the smart quotes to the left

tmutil setdestination /volumes/backupdrivename


this will tell you where the error exists and try to search for it. 
maybe a permission error. remember you maybe have to try the same command with 'sudo'

if the config is done but it won't start try to start the backup from command also 

tmutil startbackup &amp;&amp; tmutil status


you will notice that backup started at timemachine app