# ERROR 1 \[file ffbonded.itp, line 676\]: Encountered a second block of parameters for dihedral type **URL:** \ **Category:** User discussions\ **Created:** [July 27, 2020, 4:07pm UTC](https://gromacs.bioexcel.eu/t/error-1-file-ffbonded-itp-line-676-encountered-a-second-block-of-parameters-for-dihedral-type/581 "2020-07-27T16:07:41Z")\ **Posts on this page:** 1\ **Page:** 1
**Author:** ![sadaf](https://avatars.discourse-cdn.com/v4/letter/s/77aa72/32.png) [@sadaf](https://gromacs.bioexcel.eu/u/sadaf)\ **Post date:** [July 27, 2020, 4:07pm UTC](https://gromacs.bioexcel.eu/t/error-1-file-ffbonded-itp-line-676-encountered-a-second-block-of-parameters-for-dihedral-type/581/1 "2020-07-27T16:07:41Z")
GROMACS version:2020 GROMACS modification: Yes/No Here post your question Dear Gromacs users I need your kind suggestions on the problem I’m facing as below:- I have a small ligand molecule for which I used acepype to generate topology. I want to use amber-99SB-ILDN forcefield for the protein so I added this forcefield into my local directory and followed the procedure mentioned in [http://manual.gromacs.org/current/how-to/topology.html](http://manual.gromacs.org/current/how-to/topology.html) However, I get the following error:- ERROR 1 [file ffbonded.itp, line 676]: Encountered a second block of parameters for dihedral type 9 for the same atoms, with either different parameters and/or the first block has multiple lines. This is not supported. I looked for the error and got that there is some duplication to the parameters which already exist in forcefield. After removing these bonded interactions ; bondtypes, angletypes and dihedraltypes I get a new error:- ERROR 1 [file topol.top, line 16431]: No default Bond types ERROR 142 [file topol.top, line 73819]: No default Proper Dih. types I am not getting if 1 thing; GAFF parameters which I obtained from acepype have lowercase naming and different atomtypes, If these parameters exiist in forcefiled how can I recognise for each parameter. Could you please help me to fix this problem. Thanks in advance. Regards Sadaf