MSDTC on server 'server is unavailable'

I get this weird error on SQL Server. And I cannot find solution in older posts.

I have this procedure:

create proc _upJM_SyncAll_test
as
begin
    DECLARE @SQLString nvarchar(max)

set @SQLString = N'
DELETE FROM OPENQUERY([LOCAL_MYSQL],''SELECT acSubject FROM _utjm_setitemprices'') where acSubject not in (select acSubject from _uvJM_SetSubj)
DELETE FROM OPENQUERY([LOCAL_MYSQL],''SELECT acSubject FROM _utjm_setsubj'') where acSubject not in (select acSubject from _uvJM_SetSubj)

update a
set acName2 = b.acName2,
	acName3 = b.acName3,
	acAddress = b.acAddress,
	acPost = b.acPost,
	acPostName = b.acPostName, 
	acCountry = b.acCountry, 
	acVATCodePrefix = b.acVATCodePrefix,
	acCode = b.acCode, 
	anDaysForPayment = b.anDaysForPayment
from OPENQUERY([LOCAL_MYSQL],''SELECT * FROM _utjm_setsubj'') a join _uvJM_SetSubj b on (a.acSubject = b.acSubject)
where 1=1
and (	isnull(a.acName2,'''') <> isnull(b.acName2,'''') OR 
		isnull(a.acName3,'''') <> isnull(b.acName3,'''') OR 
		isnull(a.acAddress,'''') <> isnull(b.acAddress,'''') OR 
		isnull(a.acPost,'''') <> isnull(b.acPost,'''') OR 
		isnull(a.acPostName,'''') <> isnull(b.acPostName,'''') OR 
		isnull(a.acCountry,'''') <> isnull(b.acCountry,'''') OR 
		isnull(a.acVATCodePrefix,'''') <> isnull(b.acVATCodePrefix,'''') OR 
		isnull(a.acCode,'''') <> isnull(b.acCode,'''') OR 
		isnull(a.anDaysForPayment,'''') <> isnull(b.anDaysForPayment,'''')
)

insert into OPENQUERY([LOCAL_MYSQL],''SELECT * FROM _utjm_setsubj'') (acSubject, acName2, acName3, acAddress, acPost, acPostName, acCountry, acVATCodePrefix, acCode, anDaysForPayment)
select b.acSubject, b.acName2, b.acName3, b.acAddress, b.acPost, b.acPostName, b.acCountry, b.acVATCodePrefix, b.acCode, b.anDaysForPayment
from OPENQUERY([LOCAL_MYSQL],''SELECT * FROM _utjm_setsubj'') a right join _uvJM_SetSubj b on (a.acSubject = b.acSubject)
where a.acSubject is null '

EXECUTE sp_executesql @SQLString;
end

When I run procedure in management studio like this:

  exec dbo._upJM_SyncAll_test

everything is OK. I get no error, sync is working just fine.

But when I put execute in trigger like this:

create trigger _utrJM_SetSubj on tHE_SetSubj after insert, update, delete
as
begin
    exec dbo._upJM_SyncAll_test
end

I get this error:

> Msg 8501, Level 16, State 3, Procedure _upJM_SyncAll_test, Line 54
> MSDTC on server 'server' is unavailable.

Procedure _upJM_SyncAll_test has only 39 lines...

In my case, the service was stopped. solution: need to turn the MSDTC service on

1. go to Services. (START > SETTINGS > CONTROL PANEL > ADMINISTRATIVE TOOLS > SERVICES)
2. Find the service called 'Distributed Transaction Coordinator' and RIGHT CLICK (on it and select) > Start.
3. make this service to run Automatically for solving this issue permanently

Triggers are included in the implicit transaction required for insert, update, and delete statements. Because you are connecting to a linked server within a transaction, SQL Server promotes it to a Distributed Transaction.

You'll need to configure MSDTC, you can either open MMC and load the MSDTC plugin or use the following script to open inbound and outbound transactions.

https://technet.microsoft.com/en-us/library/cc731495.aspx

REG QUERY "HKLM\Software\Microsoft\MSDTC\Security" /v NetworkDtcAccess
REG QUERY "HKLM\Software\Microsoft\MSDTC\Security" /v NetworkDtcAccessTransactions
REG QUERY "HKLM\Software\Microsoft\MSDTC\Security" /v NetworkDtcAccessInbound
REG QUERY "HKLM\Software\Microsoft\MSDTC\Security" /v NetworkDtcAccessOutbound
PAUSE

REG ADD "HKLM\Software\Microsoft\MSDTC\Security" /f /v NetworkDtcAccess /t REG_DWORD /d 1
REG ADD "HKLM\Software\Microsoft\MSDTC\Security" /f /v NetworkDtcAccessTransactions /t REG_DWORD /d 1
REG ADD "HKLM\Software\Microsoft\MSDTC\Security" /f /v NetworkDtcAccessInbound /t REG_DWORD /d 1
REG ADD "HKLM\Software\Microsoft\MSDTC\Security" /f /v NetworkDtcAccessOutbound /t REG_DWORD /d 1
PAUSE

net stop MSDTC
net start MSDTC
PAUSE

I ran into the same error, however it wasn't as simple as the Distributed Transaction Coordinator service from not running. I received a driver update automatically through windows that was causing issues with COM+ and not allowing MSDTC to communicate properly even though the MSDTC service was running. In my case, it was an issue with HP hotkey drivers but in researching I found other reports of issues with audio drivers from other manufacturers causing this as well.

To check to see if you have a similar issue, launch Component Services (dcomcnfg.exe), then expand Component Services > Computers > My Computer, from here click on 'COM+ Applications' to see if an error will pop-up with "COM+ unable to talk to Microsoft Distributed Transaction Coordinator" or there will be a red error over the icon for My Computer in the navigation.

The fix for me was to disable the 'HP Hotkey Service" and "HotKeyServiceUWP" services. Once those were disable, MSDTC immediately started working.

My issue was resolved by disabling a conflicting service/driver. I disabled all of my HP services (HP App Helper, HP CASL, HP System Info), and now it works fine.

'Distributed Transaction Coordinator' service was not running, So started service and changed service type to automatic too.

In my case I had a named instance of Microsoft SQL Server at a remote server and the error output of my application looked like this:

System.Data.SqlClient.SqlException (0x80131904): MSDTC on server 'SERVER\INST_NAME' is unavailable.

Experimenting with the SQL connection string, such as replacing the SERVER\INST_NAME with SERVER,TCP_PORT_NUMBER did not help. I was still getting the same error and I decided to install a default instance (MSSQLSERVER) so that the SQL Server name became SERVER only. This solved the problem as the RPC and MSDTC started resolving the name.

Powershell solution:

Get-Service -Name MSDTC | Set-Service -StartupType Automatic

Recently this appeared as an issue on my work machine (Win 10, MSSQL 2016 SP2 Express). I do not have linked servers. This appeared from nothing. The MSDTC service is running, MSSQL works fine using the Mgmt Studio. However my .NET 4.7.1 Unit test app refuse to connect with the database with that "MSDTC on server '...' is unavailable" error.

The temporal workaround I found is to add "Enlist=False;" at the end of the connection string to avoid using MSDTC at all for the connection.

The source for this solution is a comment under this topic: https://docs.microsoft.com/en-us/archive/blogs/distributedservices/intermittent-error-msdtc-on-server-servername-is-unavailable