Increase PHP memory limit: You can try increasing the memory limit in your PHP configuration file (php.ini). Look for the memory_limit directive and set it to a higher value, such as 256M or 512M, depending on your needs.
Check for memory leaks: Memory leaks can cause PHP to exhaust its memory allocation quickly. Review your code for any potential memory leaks, such as unclosed database connections or large objects that are not properly released.
Optimize code and reduce memory usage: Review your code and optimize it to reduce memory consumption. This can include using more efficient algorithms, avoiding unnecessary data duplication, and releasing memory when it's no longer needed.
Use caching: Implementing caching mechanisms can help alleviate memory usage by storing frequently accessed resources in memory. Consider using solutions like Memcached or Redis to cache data and reduce the need for PHP memory.
pgrade hosting resources: If you've tried the above steps and still encounter memory issues, it might be necessary to upgrade your hosting resources. Contact your hosting provider to discuss options for increasing memory allocation.

Remember to monitor your PHP application for memory usage regularly and make adjustments as necessary to prevent future "Out of memory" errors.