Can I remove an expired Self-Signed certificate?

Hi Saddam,

You need to do:

1) Create a new Self-Signed Certificate by going to Setup -> Certificate and Key Management
2) You need to go to Setup -> Identity Provider and change the expired certificate for the one created in step 1
3) you need to go to Setup -> Create -> Apps and check if any connected app is using the Certificate, if it does, replace it for the one created in Step 1
4) Go again to Setup -> Certificate and Key Management and delete the expired certificate
5) repeat this for anu other sandbox you have notifications from