If you get a warning like "DONOTCACHEPAGE constant is defined" or "DONOTCACHEPAGE is defined as TRUE", you need to remove this constant. Let me show how to remove it.
ssh -p 2222 user-name@hosting-ip-address
e.g. ssh -p 2222 email@example.com
First of all, you need to have SSH connection. If you don't have, please contact to your hosting provider.
e.g. grep -r DONOTCACHEPAGE /public_html/
After connection, you can grep the keyword.