Google Search Console - Sitemap-problem

very necessary*
I have a problem about Google Search Console - Sitemap
after upload sitemap, we received that
Why pages aren’t indexed
Pages that aren’t indexed can’t be served on Google:
Duplicate without user-selected canonical 28 pages
Blocked due to access forbidden (403) 26 pages
Discovered - currently not indexed 113 pages
Crawled - currently not indexed 19 pages

what do I do to improve this problem?
In addition, google scholar sometimes not read my article?

What application are you using?

Additional information

Hi @Reza_Lotfi,

We do offer some advice on troubleshooting Google Scholar here:

This may not be exactly applicable to your situation, but may be worth looking at. Also, OJS 3.1 is quite out of date and no longer supported - I highly recommend upgrading to a later version like OJS 3.3 or 3.4 - you may find that these issues improve as a result of upgrading (although that is not guaranteed).

PKP Team