There is also option in defect tracking tools for comments by developers. When developer rejects some defect on defect tracking tool, he also mention his or her comments there. You can read that for the reason of rejecting. Then you can personally discuss with the developer.

Often it happens that a defect coming on your pc does not happen in developer pcs. It is said as defect has not REPRODUCED on developer pc. Tester should first check this on his own machine that whether is coming or not. Then tester job is then to try to reproduce it on the developer pc.

There may be several reasons due to which defect is not reproduced on developer pc. Few of them mentioned below(mostly related to web applications):

1. Check the configuration of your application whether it is same on your pc and developer pc. For example there may be some configuration parameter in your application which you are testing that may not be set same in developer pc as it is on your testing environment.

2. Check the configuration of browsers on which you are testing your application if it is web application. For example in IE often this issue raised due to the different document modes(by pressing f12 in IE).

Another example of this is compatible modes setting on developer and tester browsers should be same.

3)Screen layout defects can be rejected due to different screen resolutions on tester and developer machines.

4)Often just cleaning the cache of browsers of developer machine sometimes reproduced the defect.

5. Often it happens that developer has tested it on desktop while tester has tested it on laptops.

6. Often it happens that tester raise some defect but that is just coming due to refreshing not done since long time on your application being tested. These defects do not come on developer machines so got rejected.

7. Some times developers do not check it carefully(there may some negligence on their part). In this case tester should consult developer and try to reproduce the defect on their machines.

There is also option in defect tracking tools for comments by developers. When developer rejects some defect on defect tracking tool, he also mention his or her comments there. You can read that for the reason of rejecting. Then you can personally discuss with the developer.

Often it happens that a defect coming on your pc does not happen in developer pcs. It is said as defect has not REPRODUCED on developer pc. Tester should first check this on his own machine that whether is coming or not. Then tester job is then to try to reproduce it on the developer pc.

There may be several reasons due to which defect is not reproduced on developer pc. Few of them mentioned below(mostly related to web applications):

1. Check the configuration of your application whether it is same on your pc and developer pc. For example there may be some configuration parameter in your application which you are testing that may not be set same in developer pc as it is on your testing environment.

2. Check the configuration of browsers on which you are testing your application if it is web application. For example in IE often this issue raised due to the different document modes(by pressing f12 in IE).

Another example of this is compatible modes setting on developer and tester browsers should be same.

3)Screen layout defects can be rejected due to different screen resolutions on tester and developer machines.

4)Often just cleaning the cache of browsers of developer machine sometimes reproduced the defect.

5. Often it happens that developer has tested it on desktop while tester has tested it on laptops.

6. Often it happens that tester raise some defect but that is just coming due to refreshing not done since long time on your application being tested. These defects do not come on developer machines so got rejected.

7. Some times developers do not check it carefully(there may some negligence on their part). In this case tester should consult developer and try to reproduce the defect on their machines.

A similar question can be found at ui-validation-bug-not-reproducible-on-dev-environment