Any ideas why can't add more than 971 products?

Also notticed that some of the products missing from the admin area but they are still in database...
Thanks for hints
Hi @PrestaShark,
We need to retrieve the PHP error log and the debug mode report in order to find out what's wrong.
Thanks!
@PrestaShark, I tried with PS1.6.1.23 & it is ok.

Thanks!
Something was mismatched with database. After clean and fresh product upload everything is fine now. Closed. Thanks for Your time @khouloudbelguith
@PrestaShark, thanks for your feedback.
Feel free to open a new when needed.
Thanks!