[SOLVED] Error 404 when including profile or banner image

Hello please,
When users want to upload image profile and canvas,
It appears the error

THE REQUESTED PAGE CAN NOT BE FOUND.
404 Product not found

What can be happening?
thanks
jc

Enable debug mode and maximum error reporting in Joomla global configuration then retry to see if any errors output. If no errors and SEF is enabled then disable SEF to see if it's a URL rewrite problem. If that's not it check server error logs as the upload maybe blocked by mod_security setup by your host.

I have done everything that you indicate and it continues happening, the rare thing that does not happen to all the users.
For example, if the user already had an image, you can change it without problems.
The problem is when you are new and want to upload a new image to the profile or canvas.
I have the PHP 7.1 I've gone down to 5.6, The error.log file was generating many errors in adsmanager because of php 7.0.

I do not know what to do

Clear the error log and retest then review the error log on a failed attempt to see what's going on. A 404 doesn't make any sense to an image upload. If you've SEF enabled try disabling it and see if it's a URL rewrite issue.

Do not use PHP 7. Many extensions are not completely compatible with it yet (including CB due to 3rd party Guzzle and Imagine libraries). Use latest PHP 5.6 for the time being until we can patch PHP 7 issues with our 3rd party libraries.

Ok,. Now when uploading the image comes out error 403.html

I'm going to disable image upload.

403 is a forbidden error. Check your server error logs. It sounds like probably mod_security blocking uploads (bad filename?) or you've a 403/404 redirect setup in htaccess maybe.