2020 "Strict Transport Security is not set to at least 15552000 seconds

Strict Transport Security is not set to at least 15552000 seconds

Just discovered this warning in Nextclud Admin area. The problem was actually solved.
I configure my servers with the help of KeyHelp and as you can see in the picture, HSTS is set to 180 days.

Does this message appear again maybe because I switched from PHP 7 to PHP 7.3?

No, its a Webserver setting as far as i remember. I used to put a line somewhere in apache, to config this.

Okay, I found the cause.
I ran the check again on another computer and this message did not appear.
So it seems to be a browser problem. The browser on which the message appears is on a company computer and it seems that the settings of the browser is a bit restrictive.