Noisy fan in iMac 21.5

Hi. I have an iMac that use to work perfectly. Few days ago, I start hearing this noisy continous sound from the fan. I browse some topics here and did the rest thing ( Shutting down the device, unplug, wait 15 seconds, replug) I also downloaded the SMC fan control. Now, I see the rpm 1440'sh and temprture is 44 C.

any suggestion?