5.7.520 Message blocked because it contains content identified as spam. AS(4810)

********SOLUTION and the cause are in the user computer *****


After 2 days working to sort the problem SOLUTION:

The Problem: Virus - malwares.

The problem was just happening when attaching files on the email .
The problem in my case was happening only in the Opera Browser .
The test did sending from mobile and Mozilla Firefox was fine .

Than a conclusion of some possible problems started extensions I had allowed on Opera .
Also coincident or not I was trying to setup some smart plug using EWELINK the while I was doing the configuration some settings were drastic change in my network by using this application to setup the smart plugs … if you every want use any cctv cameras or any this smart plugs don’t attach it in your local area network …. I always avoid but this time I was did not want create a VPN or setup a separate swich and end up in troubles as it …..


solutions:
reset windows firewall for default.
reset network for default.

Remove and uninstall all extensions from all your browsers.

running “eset online scanner” than remove all virus .
running Malwarebytes scanner and go in settings and mark deep check root fixed option.

Finalising open the windows virus and Theat protection and do all options available there .. deep check and others will restart computer to do the check.



My problem now sorted .

Why was come this message returning emails? Possible trojan on the files I was trying attaching from my computer and then the reason the message here while emails without attachment or zip compacted was not detected by the Microsoft .
Remote server returned '550 5.7.520 Message blocked because it contains content identified as spam. AS(4810)