Allowed memory size of 33554432 bytes exhausted

I have a problem when I try to run my application, because then I have an application made with doctrine + php and a while ago started to give this error:

PHP Fatal error:  Allowed memory size of 33554432 bytes exhausted 
(tried to allocate 8388608 bytes) 
 in /home/mentorsitescom/public_html/prefeituraexemplo/mpe-serv-sol-desenv/vendor/doctrine/annotations/lib/Doctrine/Common/Annotations/DocParser.php on line 236

I have tried to set via php the memory limit for:

ini_set('memory_limit', '2048M');

or to

ini_set('memory_limit', '-1');

But the error still continues, can anyone help me?