Hello Stefan,
Thank you for getting back to us.
We know you mentioned this seems to happen more randomly, and it doesn't appear to be related to any applications you've installed. Some other possibilities this can be stemming from could be the type of network you're connecting to, or an email account setup on your device.
-When this alert pops up, can you take notice to the type of network you're connected to, please? Are you connecting your iPhone to cellular data, private Wi-Fi, VPN, public Wi-Fi, etc.? Connect iPhone to the internet. If you find this pop up occurs when connecting to one particular Wi-Fi network, perhaps try forgetting the network under Settings > Wi-Fi > tap the i > tap Forget This Network. Then, connect to it again to provide a fresh connection, if desired.
-Do you have any email accounts setup on your iPhone that could be related to, or connecting to, an euk server or cPanel, Inc.? Add an email account to your iPhone, iPad, or iPod touch. Navigate to Settings > Mail > Accounts. From there, you can tap on your email account(s), then tap the account name at the top of that next page to view more of the mail settings, such as the SMTP server, etc. If you find this is related to a specific email account, perhaps try deleting the account from your iPhone and adding it as new again.
Keep us posted on what you find.
Cheers!