# Problem while generating JZ4 Topology with CGenFF

**URL:** <https://gromacs.bioexcel.eu/t/problem-while-generating-jz4-topology-with-cgenff/1366>\
**Category:** User discussions\
**Created:** [January 1, 2021, 9:14am UTC](https://gromacs.bioexcel.eu/t/problem-while-generating-jz4-topology-with-cgenff/1366 "2021-01-01T09:14:37Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![Leena](https://avatars.discourse-cdn.com/v4/letter/l/d78d45/32.png) [@Leena](https://gromacs.bioexcel.eu/u/Leena)\
**Post date:** [January 1, 2021, 9:14am UTC](https://gromacs.bioexcel.eu/t/problem-while-generating-jz4-topology-with-cgenff/1366/1 "2021-01-01T09:14:38Z")

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GROMACS version:2020.3  
GROMACS modification: Yes/No  
Here post your question  
Could you please help me with the screenshot attached?

 ![Python screenshot](https://europe1.discourse-cdn.com/flex017/uploads/bioexcel1/original/1X/8fda376cbda72465bf9e9f230b1b3b0b426a62a5.png)

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**Author:** ![yyten](https://avatars.discourse-cdn.com/v4/letter/y/839c29/32.png) [@yyten](https://gromacs.bioexcel.eu/u/yyten)\
**Post date:** [January 2, 2021, 1:26pm UTC](https://gromacs.bioexcel.eu/t/problem-while-generating-jz4-topology-with-cgenff/1366/2 "2021-01-02T13:26:38Z")

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You need to have the str file (Generated from CGenFF server) in the same folder.

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**Author:** ![Leena](https://avatars.discourse-cdn.com/v4/letter/l/d78d45/32.png) [@Leena](https://gromacs.bioexcel.eu/u/Leena)\
**Post date:** [January 3, 2021, 8:36am UTC](https://gromacs.bioexcel.eu/t/problem-while-generating-jz4-topology-with-cgenff/1366/3 "2021-01-03T08:36:13Z")

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Thank you for the response. It worked.