Hi @robert.pal
I wonder if it due to some server based security.
There is a known issue with some servers tripping up when saving a URL value, so perhaps this is the same problem.
The solution in these cases was to add the following to the .htaccess
file:
<IfModule mod_security.c>
SecFilterEngine Off
SecFilterScanPOST Off
</IfModule>
Hope that helps