PutEmail Timeout smtp.office365

[#1]

Hello everyone, 

I have been trying to solve an issue on my on-prem NiFi 2.4.0 application for a month which being PutEmail timeout errors. Specifically, we were using NiFi 1.9.0 and local smtp server to send mails, after updating to 2.4.0 we started using office365 smtp server. 

swaks --server smtp.office365.com --port 587 --tls --helo test.local --auth LOGIN --auth-user notifymail@****.com --auth-password '****' --from notifymail@****.com --to okan.ergun@****.com --header "Subject: Test Email" --body "Test SMTP Relay Service"

With the command above I never had timeouts, and every mail was successful from the application environment, although NiFi gets timeouts time to time and doesn't have any specific times to have timeouts.

Processor Details:

SMTP Hostname	smtp.office365.com
SMTP Port	587
Authorization Mode	Use Password
SMTP Username	notifymail@****.com
SMTP Password	Sensitive value set
SMTP Auth	true
SMTP STARTTLS	true
SMTP Socket Factory	${literal('')}
SMTP X-Mailer Header	NiFi
Attributes to Send as Headers (Regex)	No value set
Content Type	text/plain
From	notifymail@****.com
To	okan.ergun@****.com
CC	No value set
BCC	No value set
Reply-To	No value set
Subject	Test from NiFi
Message	Test
Flow file content as message	false
Input Character Set	UTF-8
Attach File	true
Include All Attributes In Message	false

PutEmail[id=99041462-0dcf-31ed-e46c-45b560f51973] Failed to send email for FlowFile[filename=48b2d732-915c-4a3e-a5d4-a1c0cdcb1e7c]: Couldn't connect to host, port: smtp.office365.com, 587; timeout -1; routing to failure: org.eclipse.angus.mail.util.MailConnectException: Couldn't connect to host, port: smtp.office365.com, 587; timeout -1;
nested exception is:
java.net.ConnectException: Connection timed out
- Caused by: java.net.ConnectException: Connection timed out

2026-02-25 13:24:41,375 ERROR [Timer-Driven Process Thread-5] o.a.nifi.processors.standard.PutEmail PutEmail[id=99041462-0dcf-31ed-e46c-45b560f51973] Failed to send email for StandardFlowFileRecord[uuid=48b2d732-915c-4a3e-a5d4-a1c0cdcb1e7c,claim=,offset=0,name=48b2d732-915c-4a3e-a5d4-a1c0cdcb1e7c,size=0]: Couldn't connect to host, port: smtp.office365.com, 587; timeout -1; routing to failure

org.eclipse.angus.mail.util.MailConnectException: Couldn't connect to host, port: smtp.office365.com, 587; timeout -1

at org.eclipse.angus.mail.smtp.SMTPTransport.openServer(SMTPTransport.java:2243)

at org.eclipse.angus.mail.smtp.SMTPTransport.protocolConnect(SMTPTransport.java:729)

at jakarta.mail.Service.connect(Service.java:364)

at jakarta.mail.Service.connect(Service.java:222)

at jakarta.mail.Service.connect(Service.java:171)

at jakarta.mail.Transport.send0(Transport.java:230)

at jakarta.mail.Transport.send(Transport.java:100)

at org.apache.nifi.processors.standard.PutEmail.send(PutEmail.java:654)

at org.apache.nifi.processors.standard.PutEmail.onTrigger(PutEmail.java:497)

at org.apache.nifi.processor.AbstractProcessor.onTrigger(AbstractProcessor.java:27)

at org.apache.nifi.controller.StandardProcessorNode.onTrigger(StandardProcessorNode.java:1272)

at org.apache.nifi.controller.tasks.ConnectableTask.invoke(ConnectableTask.java:244)

at org.apache.nifi.controller.scheduling.AbstractTimeBasedSchedulingAgent.lambda$doScheduleOnce$0(AbstractTimeBasedSchedulingAgent.java:59)

at org.apache.nifi.engine.FlowEngine.lambda$wrap$1(FlowEngine.java:105)

at java.base/java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:572)

at java.base/java.util.concurrent.FutureTask.run(FutureTask.java:317)

at java.base/java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:304)

at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1144)

at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:642)

at java.base/java.lang.Thread.run(Thread.java:1583)

Caused by: java.net.ConnectException: Connection timed out

at java.base/sun.nio.ch.Net.connect0(Native Method)

at java.base/sun.nio.ch.Net.connect(Net.java:589)

at java.base/sun.nio.ch.Net.connect(Net.java:578)

at java.base/sun.nio.ch.NioSocketImpl.connect(NioSocketImpl.java:583)

at java.base/java.net.SocksSocketImpl.connect(SocksSocketImpl.java:327)

at java.base/java.net.Socket.connect(Socket.java:751)

at java.base/java.net.Socket.connect(Socket.java:686)

at org.eclipse.angus.mail.util.SocketFetcher.createSocket(SocketFetcher.java:368)

at org.eclipse.angus.mail.util.SocketFetcher.getSocket(SocketFetcher.java:243)

at org.eclipse.angus.mail.smtp.SMTPTransport.openServer(SMTPTransport.java:2193)

... 19 common frames omitted

2026-02-25 13:24:41,375 INFO [Timer-Driven Process Thread-5] o.a.n.c.s.StandardProcessScheduler Stopping PutEmail[id=99041462-0dcf-31ed-e46c-45b560f51973]

Thank you for responding before-hand, I would appreciate any criticism also.

[#2]

@okanergun Welcome to the Cloudera Community!

To help you get the best possible solution, I have tagged our NiFi experts @MattWho @mburgess  who may be able to assist you further.

Please keep us updated on your post, and we hope you find a satisfactory solution to your query.

[#3]

Hello @okanergun, 

According to https://issues.apache.org/jira/browse/NIFI-8630 the PutEmail processor was updated as mentioned here: 
"Upgraded javax.mail 1.4.7 to jakarta.mail 2.0.1 for PutEmail"
That was on 1.14.0, so in your case, you were using the old javax.mail and not the new jakarta.mail. 
There is a difference on the environment to take in consideration. 

The log you shared shows this: 

Couldn't connect to host, port: smtp.office365.com, 587; timeout -1

This means you do not have a socket timeout defines, which could case the processor to hang and report those timeouts when OS tells so. 
You can try to add these setting: 
-Dmail.smtp.connectiontimeout=30000
-Dmail.smtp.timeout=30000
-Dmail.smtp.writetimeout=30000
https://eclipse-ee4j.github.io/angus-mail/docs/api/org.eclipse.angus.mail/org/eclipse/angus/mail/smt... 

Also, make sure you have "Concurrent Tasks" under the PutEmail processor set to 1. 
This kind of SMTP for Microsoft may block parallel connections. 

[#4]

@okanergun Has the reply helped resolve your issue? If so, please mark the appropriate reply as the solution, as it will make it easier for others to find the answer in the future. Thanks.