Hi I asked for support for your post, but it’d be helpful when you add DHIS2 instance version…etc and if this warning is affecting your instance in anyway. @Calle_Hedberg had complained about this issue too, and this has been mentioned here: Weekly dataset report generation problem
Can you send a screenshot of the login page when that error occurs ?
In the error logs, the message is " IO Error rendering template /dhis-web-common/security/login.vm". It seems that the server couldn’t open the file login.vm. Did you try redeploy the war file ? Could it be a server access permission issue ?