Suspend User through API returns error code

[ioigoume]

When trying to suspend a user through the API

voms-admin --vo test-vo --host test-vo.example.com --nousercert suspend-user "/O=FOO/OU=AAI-Pilot/O=FOO Foundation/CN=John Doe kokfTSdakods2nTATTA" "/O=FOO/OU=AAI-Pilot/CN=FOO Simple Demo CA" 'Expired...'

On VOMS UI the status of the user changes but we get an error response from the server. The response is:

The server could not answer the request for https://test-vo.example.com:8443/voms/test-vo/apiv2/suspend-user.action. HTTP Error 500: Java heap space

Process finished with exit code 255

On the server side the logs contain the following error message:

2021-02-11 12:46:09.551Z - [test-vo] WARN [qtp112619572-38183] [DefaultJSONWriter] - JavaScript doesn't support non-String keys, using toString() on org.glite.security.voms.admin.persistence.model.VOMSAdmin

The message repeats itself for 70K-80K times until the Java heap is full. Then VOMs self-terminates the process and returns to the client with the error message.

Affects version 3.8.0