E-mail from my Homey

Can see the following in my routers log, every 15 minutes:

Lördag, Okt 24,2020 06:24:58
[email failed] fail to connect to outgoing mail server, Lördag, Okt 24,2020 05:55:14
[DOS Attack] : 6 [Smurf] packets detected in last 20 seconds, source ip [192.168.0.17].

IP-address 192.168.0.17 is my Homey.
Why is Homey try to send an e-mail?

It’s not. The “DOS Attack” takes place as 05:55, the e-mail is sent at 06:24. I think it’s your router that’s trying to send e-mail (perhaps a status report).

FWIW, it’s not a DOS attack either, Smurf attacks haven’t worked for more than 20 years. Homey uses broadcast pings to find devices on your local network, and your router is mistaking those for Smurf packets.