Okay, it now works... I am facing a different issue now. Please see what it tells me below. I definitely don't want pages and posts to be blocked. Also, am I supposed to submit in all sitemap: author, pages, post, etc?
#
Type
Issue
Description
Issues count
Example
Line
Detected
1
Warnings
Url blocked by robots.txt.
Sitemap contains urls which are blocked by robots.txt.
6
Value: https://domainname.com/author-sitemap.xml
-
Feb 11, 2019
Value: https://domainname.com/category-sitemap.xml
-
Feb 11, 2019
Value: https://domainname.com/page-sitemap.xml
-
Feb 11, 2019