Could not improve 404 error and there is no result matching on Google search

[RichardPham]

Dear ladies and gentlemen,
I am An Pham, from Vietnam.I am a newbie in making weebly site. Within my ability, I am not sure whether troubles are serious or not, so I would like to listen your advice.

At first, I make a website with a long subdomain like this: https://dat-khu-cong-nghiep-tai-dong-nai.weebly.com/ (1), it was very long due to my lack of experience in website. After reading an article, I supposed that long URL could affect the SEO, so I change a new subdomain like this: https://locan-binhsoniz.weebly.com/ (2), and it is shorter. However, my trouble is:

1. When I changed into new domain (2), at least two results of the subdomain (1) like: https://dat-khu-cong-nghiep-tai-dong-nai.weebly.com/xyz.... appeared on search but appear 404 error. I tried to redirect these sites to (2) as the guideline of expert (making 404 page), but 404 still occured and empty results (1) still appeared and didn't redirect to (2). Whereas, results of (2) didn't appear although Google webmaster allowed pages indexed as well as Bing did, the changed things is still out of search and the empty results of (1) still appears.

2. I tried to follow guidelines of Weebly and fill in all meta keywords. I filled keywords "khu cong nghiep o dong nai" in all pages setting, worked with Google webmaster & Bing, built backlinks; however, when I type keyword "khu cong nghiep o dong nai' on search, nothing appears. Did i make any SEO faults on Weebly site?

I find frustrated due to no solution by myself. I hope that community could help me and show me the faults.

Thank you.

[Bernadette3]

Greetings.

It sounds like you need to request a recrawl of your site. 

https://support.google.com/webmasters/answer/6065812?hl=en

[RichardPham]

Thank you for your reply, Mr. Bernadette,

Of course, I did it because it a new domain. All the things I did with Google search console and do crawling already, sir.

Hope your consideration!

[Adam7]

You might want to consider publishing another site with the old domain name, then add a link on that to the shorter domain name. I would also add 301 redirects on this new site for any of your old pages to whatever page has the link to your shorter domain name. This should help send traffic to the shorter domain name and hopefully help get that indexed and ranked better.