@ francis
Please 'modify' your post
change the URL from http to hXXp or www to wXw, to break the link and avoid accidental exposure to suspect sites, thanks.
Or just post the domain without the https, e.g. i3c8h-mailer.my.cclb.io/
You are certainly right to have been suspicious, this really wouldn't be normal from any sort of legit support being this obscure.
This appears to be an attempt to steal your logon details and password.
Also see
https://sitecheck.sucuri.net/results/cclb.io which is the actual domain at the last part of your url. Considered a medium security risk and even that redirects to codecollab.io