XF 1.5 Unable to install themes

[Alhidayah]

Hi, i am unable to install any themes, when i upload the xml file its says

This site can’t be reached​

i have tried with different browser as well, but it did not work, i have tried with couple of themes and its says the same thing, and there are no error in the log.
Does any one know the solution.....
Thank you.

 

[Paul B]

and there is error in the log

What is the error?

 

[Alhidayah]

Oh sorry, there was a typo, i meant to say, there are no errors in error log, i am able to install add ons, but not themes

 

[Alhidayah]

There are still no errors in server error log, I tried turning off the board to install the theme and it does not work as well, i am trying to install cloud theme https://xenforo.com/community/resources/cloud.3407/ and my xenforo version is 1.5.24, is there anyway to troubleshoot this issue?.