I don’t have the issue that you guys are mentioning but I am using Matomo self-hosted on a domain to track multiple domains.
None of the domains I am tracking is showing the deceptive error message.
But as per what @heurteph-ei said:
I checked the github page above:
Findus23 commented Jan 21, 2023
This looks a lot like your Matomo domain is on the google safe browsing list.
You can check here:
https://transparencyreport.google.com/safe-browsing/searchAnd report an incorrectly blocked site here:
https://safebrowsing.google.com/safebrowsing/report_error/?hl=en
and ran my site(s) through https://transparencyreport.google.com/safe-browsing/search and got no error status back on them.
Maybe this is also a way to check if the flag error went away after submitting the review to Google.
From the looks of it, at least from my point of view, seems to be a server IP issue, maybe the IP was flagged (if you are using shared hosting I’d exclude for the IP to be flagged).