What's my blog URL?

That’s a wordpress.com issue, this is www.remarpro.com (for self-hosted).

You could try their wp.com support.

Why is it a .com issue? When I am logged into my WordPress admin page and click on the Help tab it takes me to the www.remarpro.com Support page. I looked up the difference on https://en.support.wordpress.com/com-vs-org/ and this description fits what I have when describing the pros and cons of .org:

www.remarpro.com (self-hosted) Benefits
Ability to upload custom themes
Ability to upload plugins
Complete control to change code if you’re technically minded

www.remarpro.com (self-hosted) Cons
You need a good web host — This generally costs $7-12 a month, or thousands of dollars per month for a high traffic site
Requires more technical knowledge to set up and run
You’re responsible for stopping spam
You’re responsible for creating and maintaining backups of your site
You’re responsible for updating the WordPress software when new versions are released
If you get a huge spike in traffic, your site will probably go down unless you have a robust hosting setup

Your first link works.

However, based on description of your second link as a sample URL, it sounded like a wordpress.com issue to me since I don’t know of anywhere on here that would show wordpress.com as a suggested sample URL.

I wanted to repost something from another WordPress blog.

Which other WordPress blog was this that had the original content? Hard to say what the issue is without knowing more about what this undefined “repost” mechanism is.