Your session timed out

I have installed PHPList, latest version v3.2.4
My PHP Server Installation version is 5.6

It was working fine in January and February 2016.
Last night, on 16th March 2016, it stopped working.
I am sure the web hosting company changed some thing inside
PHP.ini settings and their staff is not good enough to fix it.
The Login works fine, as soon as I use PHPList it logs me out after 1 to 2 minutes time.

Error: Your session timed out, please login again

This error also, shuts down the email sending process as well
and I have to re-login to re-start the email sending. I have recorded a 5
minutes video about my PHPLIST problem, please help me.

Youtube video link: