Internal Server Error on Importing Subscribers

Dear All,

I tried importing a list of subscribers of around 8000 in my newly setup phplist. It gives internal server error message in exactly around 40 seconds.

I thought it’s due to constraints in php.ini… following is the relevant config in php.ini

max_execution_time 900
memory_limit 500M
post_max_size 40M

Couldn’t find any significant error in apache error log too. What may be causing this.

Thank you