Changing the DKIM key value in Plesk without causing mail delivery outages involves a few steps. Here's a step-by-step guide:

1. Generate a New DKIM Key Pair:

   • Log in to your Plesk panel.
   • Navigate to the "Mail" tab and select the domain for which you want to change the DKIM key.
   • Scroll down to the "Mail Settings" section and click on "DKIM Settings."
   • Click on the "Switch off" button. This will remove the existing DKIM key.

2. Generate a New DKIM Key:

   • Click on the "Switch on" button again to generate a new DKIM key. Plesk will automatically generate a new key pair.

3. Update DNS Records:

   • After generating the new DKIM key, you'll need to update the DNS records for your domain. You'll have to replace the old DKIM record with the new one.
   • Log in to your DNS management interface (this might be in Plesk or through your domain registrar's control panel).
   • Find the DNS record associated with DKIM for your domain (it's usually a TXT record named something like "default._domainkey").
   • Replace the value of the old DKIM record with the value of the new one provided by Plesk.

4. Monitor DKIM Propagation:

   • DNS changes can take some time to propagate across the internet. You can use online tools to check if your new DKIM key has propagated properly.

5. Wait for DNS Propagation:

   • It's crucial to wait for DNS propagation to complete before fully relying on the new DKIM key. This process typically takes up to 48 hours, but in practice, it's often much quicker.

6. Monitor Mail Flow:

   • Keep an eye on your email flow to ensure that emails are being signed with the new DKIM key and that there are no delivery issues.

7. Verify DKIM Signature:

   • Send a test email to a service like Gmail and check the email headers to confirm that the DKIM signature is present and valid.

8. Communicate the Change (if necessary):

   • If your recipients use any email filtering or whitelisting services, it may be a good idea to inform them of the change in DKIM keys.

By following these steps, you should be able to change the DKIM key value in Plesk without causing mail delivery outages. However, always be cautious and make sure to have backups in case any unexpected issues arise during the process.