gsc error

i'm getting only one verify option on GSC. DNS option i mean. i have already verify that but i'm facing few problems like i can't see my property on google robots.txt test. even also facing some problem. i removed my property then tried again but every time i only get DNS option not HTML file or...

I have tried with several plugins, I have also tried to include a / at the end (I have seen in many pages that that solved it), but it still gives the error. Does anyone know what to do? Note: I can access the sitemap from incognito mode, also the pages to validate the sitemap read it.

I'm facing a problem in Indexing: so many posts of my blog are ranking on top but many times I noticed that it's vanished from its position. And if I manually go and index it in GSC then within a second it comes back its own position. What issue it is? Can you also faced the similar? Suggest...

lots of my posts despite being crawled Google has refused to index them. I know others had similar issue following the May update. How have you fixed it? How were you able to?

am facing this error in google search console does it affects SEO? if yea, what could be the solution(how to fix), basically my pagination URLs showing under this error.(domain.com/category/post/2/) please do suggest. I'd be highly glad for your help.

am getting a web error. somebody help me to fix it.