My institute was looking forward to use a tool provided by an external institute, but unfortunately their license terms are very strict. After talking to my advisor we decided to look for an alternative.
Two days ago I wrote a mail with the rejection to that institute. The tone of my mail was unemotional and appropriate in my opinion. I mainly said that we would have to look for an alternative tool and that it is unfortunate that we could not use the tool due to licensing problem, although there has been a very tight cooperation between the institutes in the past.
Now, my advisor sent me a mail which stated that we would have to talk and the list of communication guidelines of our institute. After reviewing my mail I understand that it could be reckoned as reproachful. Now, I feel really bad, since I am a perfectionist and I don't do such dumb mistakes usually. I am pretty new to the world of business and have a great job. Because of that mail I am very disappointed in myself.
How should I handle this situation best?
EDIT: Thank you all for your advices. I talked to my advisor and I stated the points you told me. He reacted understanding and even pointed out that he should have told me that the relation to the other institute has become worse some time ago and that I should be especially careful when talking ot them. We will figure out a plan of action for further responses now.