It will be better to reach your admin to fix this issue.
1. Lack of memory on the Server.
2. Tableau Server reached the limit of default heap space, making this error.
If the tech spec of the server got enough memory, a Tableau Server commands could eventually increase the heap space, but it need to be done with precaution.
Also are you able to download this file via Tableau Server Web UI ?
I recommend your admin to reach the tech support : Support Case | Tableau Software
He will probably need to provide the following information :
1. Date/time when you got the error message.
2. Tableau Server logs
3. Tabcmd logs
4. MSInfo to have a look on : If there is an Antivirus (with TS whitelisted in IT), the tech spec of the server