Are you entering your number with or without the comma?
Try entering just your number. No comma.
The field is expecting an input of minutes.
"100000" = 69.44 Days (just slightly under 10 weeks)
If you're still having problems, have a quick read this this article:https://www.ubbwiki.com/article/view/16/issues-with-the-php-module-suhosin.html
You can check if this installed on your server by going to
Control Panel > PHP Info
Then searching the page for "suhosin"
If you see that section, you may are probably affected by your server's settings.