keep getting connetion timeout after update to 5.5.1

Hello,

Since I update plugin vesion 5.5.1, get timeout connection regularly on my website. not sure what’s happening, but look like there are many cache crawler on db. can youhelp to check? is it due to cron even schedulle too often as well?

Request Timeout
This request takes too long to process, it is timed out by the server. If it should not be timed out, please contact administrator of this web site to increase ‘Connection Timeout’.