No Ithe propagation would affect getting to the website after it’s uploaded, not uploading it.
I notice that the screenshot (the first one) you had FTPS selected?
I took a quick look at the host help area: https://www.namecheap.com/support/knowledgebase/article.aspx/188/205/how-to-access-an-account-via-ftp
They use something called FTPES, SFTP or regular FTP. The error message you are getting is trying to use FTP-TLS ( Transport Layer Security). I think there might be an issue with using FTPS.
You might try using Regular FTP just to test everything out. I wouldn’t recommend it for a long term solution for security reasons.
I personally use SFTP for everything. I find FTPS to have a bit more difficulty (especially behind firewalls). It looks like to use SFTP with NameCheap you use the CPanel Login credentials and port 21098. To add a port to RapidWeaver simply add a
:21098 so the end of the server name.