CODEWITHSUNDEEP
sql-serverdatabaseauthenticationdatabase-performancetransient-failure
RoleyBaxter
RoleyBaxter

Reputation: 313

Transient error "Login failed for user '[UserName]'" MS SQL Server

We have been getting "Login failed for user '[UserName]'" as a transient error happening randomly for all our applications that connect to our on-premise SQL Server Database. Here is a few points to help narrow it down:

  1. The error is transient and occurs randomly at a rate of about 10 errors / day. (Our production DB is queried well over 1m times / day).

  2. As the error is rare it is mainly happening for our 2 most used service-accounts, shared between most applications (I know not best practice to have a single DB user shared between a multitude of apps, but the point is it is not isolated to a single db user). Normally this error is tied to user incorrect user credentials, but the credentials are not changing.

  3. The users are not AD users, they are SQL server Logins. (So I conclude it has nothing to do with connection to the AD services.)

  4. The errors started at a distinct point in time: the 9th Jan 2023. We had no software deployments that day. This leads me to believe that it may possibly be related to a SQL Server patch, Windows Server Update (?), or Hardware change (???). The SQL server is a single on-premise VM running in a private cluster. I don't have access to SQL server update history or any Hardware changes etc as I'm not responsible for that. (I asked the IT staff in charge of VMs if they knew of any changes but it turned up nothing.) At this moment we are running SQL Server 14.0.3456.2

I've googled a ton of course but it seems pretty much all info about this error is related to invalid credentials which does not apply here.

Is there any reasons why this error would show up in a random transient fashion?

Upvotes: 0

Views: 857

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