# "An error occurred"

**URL:** <https://www.simscale.com/forum/t/an-error-occurred/84407>\
**Category:** Solid Mechanics / FEA\
**Created:** [February 19, 2019, 9:03am UTC](https://www.simscale.com/forum/t/an-error-occurred/84407 "2019-02-19T09:03:59Z")\
**Posts on this page:** 1\
**Showing post:** 10

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**Author:** ![jousefm](https://www.simscale.com/forum/user_avatar/www.simscale.com/jousefm/32/34908_2.png) [@jousefm](https://www.simscale.com/forum/u/jousefm)\
**Post date:** [February 19, 2019, 8:34pm UTC](https://www.simscale.com/forum/t/an-error-occurred/84407/10 "2019-02-19T20:34:17Z")

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Hi Andy!

One of the issues that might cause this is that your contacts are defined arbitrarily The master and slave surface have to touch when using contact - to decide which surface is the master and which one the slave you can use this post as a help: **[Master and slave assignments](https://www.simscale.com/forum/t/master-and-slave-assignments/22254)**.

Let me know if you have done it and I will check.

Cheers,

Jousef

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