Hi There,
You might have already tried the below steps but just wanted to mention the procedure below incase something was missed.
Procedure for 1820 switch.
1. Using a small, thin tool with blunt ends (such as a paper clip), press the Reset button on the front of the switch
2. Continue to press the Reset button until the Fault LED light begins to flash.
3. Release the Reset button. The switch will then complete its self test and begin operating with its configuration restored to the factory default settings.
Its a web managed switch, If you have already tried the above steps and issue still remains than please log a case with support. Might go to RMA route.
If I have helped please give Kudos
Thanks