The below article would help you understand the procedure to create/enable an email auto responder in Plesk web hosting control panel.
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Step 1: Log into your dedicated hosting server using Plesk.
Step 2: Look for the Domains icon and Click on it.
Step 3: Now look for the domain name for which you wish to enable the auto responder. Click the domain name.
Step 4: Look for the Create Autoresponder button and Hit it.
Step 5: Populate the fields in the form.
Step 6: Check (Tick) the box against Activate Autoresponder option
Step 7: Hit the Finish button located at the bottom of the screen.
The Autoresponder is now activated for your desired domain. Please get in touch with our Windows Support Department for any assistance with enabling an autoresponder for your domain