# Simulator, XML-RPC error

**URL:** <https://forum.universal-robots.com/t/simulator-xml-rpc-error/26796>\
**Category:** Technical Questions\
**Created:** [February 14, 2023, 3:57pm UTC](https://forum.universal-robots.com/t/simulator-xml-rpc-error/26796 "2023-02-14T15:57:38Z")\
**Posts on this page:** 1\
**Showing post:** 7

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**Author:** ![cags](https://sea2.discourse-cdn.com/flex020/user_avatar/forum.universal-robots.com/cags/32/6304_2.png) [@cags](https://forum.universal-robots.com/u/cags)\
**Post date:** [February 15, 2023, 2:52pm UTC](https://forum.universal-robots.com/t/simulator-xml-rpc-error/26796/7 "2023-02-15T14:52:42Z")

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I have noticed that when it fails to call an XML-RPC server after some tries, it just gives up and keeps going. Do you need a license to install your URCap? The ones that we have at our robots don’t need one. But I have noticed from other users that URCaps that launch an XML-RPC server might encounter issues on the URSim environment, like the example of [MyDaemonSwing](https://forum.universal-robots.com/t/mydaemon-works-on-ursim3-but-not-on-ursim5/18917).

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