# Expression tag Quality

**URL:** <https://forum.inductiveautomation.com/t/expression-tag-quality/61439>\
**Category:** Ignition\
**Created:** [July 1, 2022, 4:20pm UTC](https://forum.inductiveautomation.com/t/expression-tag-quality/61439 "2022-07-01T16:20:01Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![emilio\_lasso](https://avatars.discourse-cdn.com/v4/letter/e/9dc877/32.png) [@emilio\_lasso](https://forum.inductiveautomation.com/u/emilio_lasso)\
**Post date:** [July 1, 2022, 4:20pm UTC](https://forum.inductiveautomation.com/t/expression-tag-quality/61439/1 "2022-07-01T16:20:01Z")

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I have an expression tag defined in my designer, what does is to count the time that a digital OPC tag remains as TRUE. Was working well but some days ago I realized that the Quality of the expression tag changed (i don’t know the reason) from “Good” to configuration error “server “OPC server” does not exist”, I would like to know why this happened, and which is the mechanisms the expression tags use to solve their Quality property

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**Author:** ![plo](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/plo/32/33875_2.png) [@plo](https://forum.inductiveautomation.com/u/plo)\
**Post date:** [July 8, 2022, 9:10pm UTC](https://forum.inductiveautomation.com/t/expression-tag-quality/61439/2 "2022-07-08T21:10:11Z")

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Hello Emilio,

In your gateway, is the Ignition OPC UA Server client connection up and running? What is the status on that?

Can you share a screenshot of the error?