I have searched the web and have found no tutorials to make rainloop work with cwp.. i am not a fan of the outdated roundcube.. first no built in 2fa. and the vb install scripts that pop up in cwp are for windows live mail (Microsoft’s Outlook Team announced on May 5th, 2016 that the Windows Live Mail application will reach it’s End of Life (EOL) on June 30th, 2016.).. not sure why there are setups for a dead program unless someone is just too lazy to remove unusable junk..
other issues I have seen regarding the email in cwp is that it defaults the email settings to your main domain even if your setting up emails for a different one.. of course these settings wont work but it is confusing to end users when I have to say "ignore those they aren't right " and "Use these"..