Consult with your ACS provider if they are thinking of fixing the issue of special characters in hostnames, such as spaces. Also, it could be useful if you could sniff the exchange to see what exactly is sent to your ACS and send that to support.

Can you make a support ticket?

Done.

Consult with your ACS provider if they are thinking of fixing the issue of special characters in hostnames, such as spaces. Also, it could be useful if you could sniff the exchange to see what exactly is sent to your ACS and send that to support.

I don't think it's an issue with the ACS. The XML is initially parsed by libxmljs (part of node.js) as soon as it arrives, and libxmljs fails to parse the reply from the MikroTik because it says it is invalid XML, causing GenieACS to crash since it relies on libxmljs. Perhaps it is an issue with some special character not being escaped or something. I would think it is more likely a bug in the XML that the MikroTik generates rather than the libxmljs module itself. I had encountered a bug like this before with special characters in the WPA2 key, where the MikroTik would generate a blank TR069 request to the ACS, causing a malfunction.

Spaces in the middle of hostnames appear to cause no issue, so I am not sure if the character at fault is a space or something else, it only happens with a few devices where such things appear at the end of the hostname. It might actually be a carriage return or a line feed or something, I might have to use a script to read the value of the character at fault.

Version 6.40.5 has been released:
viewtopic.php?f=21&t=127485