Alerts are sent too late after trigger

I have some problems with alerts via email. Sometimes the mail is sent several minutes/hours after alert is triggered.

I checked if it was a problem with my mails client but it wasn't the problem. Besides I tried with "slack" and the same error happen there.

Anybody got the same problem with alerts?

The report provides no file, test, logs, or reproducible alert configuration to start from. First reproduce the delay and compare email and Slack delivery timing; done means identifying the cause and verifying that triggered alerts are delivered promptly through both channels.

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