Unable to create a goal

Hello,
I installed matomo in my website but when I try to create a goal I get the following error:
“Oops… there was a problem during the request. Maybe the server had a temporary issue, or maybe you requested a report with too much data. Please try again. If this error occurs repeatedly please [contact your Matomo administrator]”.

I looked différent posts about this problem but I did not find any solution
Thanks

Hi @nickg
I suggest you have a look in the Matomo error log file:

hi
there is no informations in error log file ( I use Logviewer plugin)
Where is le error log file ?