why my website appear many soft 404 pages

[williswang]

I don’t know what happened in the last month.
I updated the article as usual, but in the last month, Google’s index has been declining and errors have continued to appear.
i dont know what is this：why
Submitted URL seems to be a Soft 404
Have you ever encountered such a problem?
please help！
example：
This Soft 404 page ，url is right，but 301
this page url ：https://www.jotrin.com/product/parts/roe0008akce00 to
https://www.jotrin.com/product/parts/ROE0008AKCE00

Why prompt Soft 404 ？
what is Soft 404？
how can cause Soft 404？
hope friend in this group ，help me，thank you in advance！

The website index has been falling, which makes me very depressed.

help my friends give some suggestions，thank you in advance

[herry123]

check out broken link from brokenlinkchecker and dead link checker write simple on google dead link checker

this my web https://sajaginfotech.com/aso-training-surat.html

[williswang]

NO,i found the soft 404 page normal，but dont know why appear