What you mean with the same credentials? The same username and password? That sounds scary to me!
You can ask your DBA to check the SQL Server errorlog. The message 18456 is logged there, and there are details on exactly why the login failed.
Cannot connect to SQL Server - username issue
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Hugo Mendonca
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Reputation points
Trying to connect to SQL Server and getting "Login failed for user '<username>'. (Microsoft SQL Server, Error: 18456). My other colleagues are using the same credentials to log in with success. Don't know what else to do.
SQL Server Database Engine
1 answer
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Erland Sommarskog 124.9K Reputation points MVP Volunteer Moderator2025-08-26T21:41:13.85+00:00 -
Hugo Mendonca 0 Reputation points
2025-08-27T13:56:47.46+00:00 Yes, same username and password. I don't know what can be the issue.
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Erland Sommarskog 124.9K Reputation points MVP Volunteer Moderator
2025-08-27T21:05:49.01+00:00 And even less do I. I mean, you at least have some knowledge about your environment. I know absolutely nothing at all.
Did you talk with your database administrator about looking in the SQL Server errorlog?
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Hugo Mendonca 0 Reputation points
2025-08-27T21:11:54.0633333+00:00 I did. We had a long call today, but couldn't find out the issue. We though it could be my firewall, but it wasn't. I uninstalled and installed ssms 4 times and still couldn't figure out why my colleagues can connect the database and I can't. My IT guy added me to the list of ips that have admin status to connect with the database. I don't know what else to do.
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Erland Sommarskog 124.9K Reputation points MVP Volunteer Moderator
2025-08-27T21:18:57.2933333+00:00 It can't be the firewall - then you would not get a login error.
But you need to look in the errorlog to find out why the login is failing.
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Hugo Mendonca 0 Reputation points
2025-08-27T22:36:58.95+00:00 Error Number: 18456
Severity: 14
State: 1
Line Number: 65536
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Erland Sommarskog 124.9K Reputation points MVP Volunteer Moderator
2025-08-28T06:27:10.5166667+00:00 No, that is what what you see in the SQL Server errorlog. The message I'm looking for will look like this:
2025-08-28 08:23:57.15 Logon Error: 18456, Severity: 14, State: 5. 2025-08-28 08:23:57.15 Logon Login failed for user 'sdfsdf'. Reason: Could not find a login matching the name provided. [CLIENT: 127.0.0.1]
What's of interest is the part that comes after Reason.
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