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There are following below Admin setting to do Enable or Disable Email sending in Magento 2.x
Step [1] – Go To STORES > Configuration, redirects on configuration.
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Step [2] – Left panel, expand Advanced > System
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Step [3] – Right Panel,
Set Yes to Disable Email Communications Dropdown
Set No to Disable Email Communications Dropdown
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Step [4] – Finally click on Save Config Button & run CLI command Flush, changes will be reflected
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