php - Strange error An error just occured please try your request again: in yii2 application

H have a yii2 application running on a server with the following specification

yii2 version: 2.0.39.3
server : vultr VPS centos 8, running PHP version 7.2.24 
web server NGINX ginx version: nginx/1.14.1

I have used it for months and everything works fine but in the past 3 days suddenly sometime it An error just occured please try sometime at the top of the page and sometime at the end of my page. This randomly appear when i refresh my server I am not sure. This happen whenever a request to the server is made and if an ajax request is made the server will receive the request but the client will receive and error message instead of a reply from he server, and also the message change the layout of the page it appears on. I have no clue as to where this could come from as i didn't do any server update of recent. Any help on this would be appreciated. attached is an image of what the error looks like from the page

Solution:

Seems this errors related with Google Site Verification API. Check if you've not enabled "Maintenance Mode" etc.