Please reproduce the issue, and then check server log to see if there are any errors. Server log can be accessed via menu Administration / System Maintenance / Server Log

The relevant issue here is that connection to mail server is closed for some reason. OneDev should try to reconnect after a short while. You may test again to see if the problem still exist.

From the error log, your mail server frequently drops connections, which causes OneDev unable to read email. What mail server are you using?

Google Workspace for the inbox.

Sendinblue to send the emails (SMTP).

Any update on this? What could be the cause/solution? How else can I investigate this issue?

I am reimplementing the mail check logic and hopefully emails will not get lost even if mail server disconnects OneDev frequently.

State changed as code fixing the issue is committed

State changed as build #2394 is successful

I'm not sure if this has been fixed, but I've got 3 support emails created over the past week that haven't had a ticket created. All from the same client (not sure if this is related or not).

Would the logs help?

I've just tried testing the Mail Settings, and it is "stuck" on:

Waiting for test mail to come back

But I can see the email in the inbox, as well as an email in the sent folder.

Although, could it be a change in timezones?

This is a new addition, but it's 20:19 and not 19:19.

2022-03-29 19:19:21,459 ERROR [JavaMail-EventQueue] i.o.s.n.DefaultMailManager Error processing mail
java.lang.IllegalStateException: This operation is not allowed on a closed folder
	at com.sun.mail.imap.IMAPFolder.checkOpened(IMAPFolder.java:478)
	at com.sun.mail.imap.IMAPFolder.getUID(IMAPFolder.java:2739)
	at io.onedev.server.notification.DefaultMailManager$5$1.messagesAdded(DefaultMailManager.java:802)
	at javax.mail.event.MessageCountEvent.dispatch(MessageCountEvent.java:154)
	at javax.mail.EventQueue.run(EventQueue.java:170)
	at java.lang.Thread.run(Thread.java:748)

Please attach the whole server log here.

Please also upgrade to build #2443 which added more trace information. To enable trace, please edit "conf/logback.xml" to add below line:

<logger name="io.onedev.server.notification.DefaultMailManager" level="TRACE"/>

I've updated to v. 7.0.3, and updated the conf file adding the code directly below the logger INFO line. Tickets are not being updated.

I can see the email in the support inbox, but the ticket isn't updated. I am not sure if it's because from the same client, or not.

Please send me all the server logs. Also please let me know timestamp of the mail in your mail box missed by OneDev.

Please upgrade to 7.0.4 which uses imap poll to check for incoming emails. This should be reliable enough and fix the issue finally (hope so, 😎 )

Could this be an issue with my network, or accessing Google (the Inbox) or Sendinblue (SMTP)? Are there any ports that I need open on my router?

No any port needs to be opened at OneDev side regarding email setup. As to the attachment encoding issue, it was fixed in build #2549

Also all logs saved locally to address this issue has been completely deleted from my local disk now.

Another ticket not being created:

2022-04-27 10:35:37,308 TRACE [pool-2-thread-5] i.o.s.n.DefaultMailManager Processing inbox messge (subject: Weekly Site Health Update, uid: 140, seq: 24)
2022-04-27 10:35:37,686 DEBUG [pool-2-thread-5] i.o.s.n.DefaultMailManager Creating issue via email (project: [project-path])...
2022-04-27 10:35:42,807 ERROR [pool-2-thread-5] o.h.e.jdbc.spi.SqlExceptionHelper integrity constraint violation: unique constraint or index violation; UKA4H1UNN42YUVXDKXL1HKTEUUX table: O_ISSUEWATCH
2022-04-27 10:35:43,164 ERROR [pool-2-thread-5] i.o.s.n.DefaultMailManager Error processing message
javax.persistence.PersistenceException: org.hibernate.exception.ConstraintViolationException: could not execute statement
	at org.hibernate.internal.ExceptionConverterImpl.convert(ExceptionConverterImpl.java:154)
	at org.hibernate.internal.ExceptionConverterImpl.convert(ExceptionConverterImpl.java:181)
	at org.hibernate.internal.ExceptionConverterImpl.convert(ExceptionConverterImpl.java:188)
	at org.hibernate.internal.SessionImpl.doFlush(SessionImpl.java:1366)
	at org.hibernate.internal.SessionImpl.managedFlush(SessionImpl.java:453)
	at org.hibernate.internal.SessionImpl.flushBeforeTransactionCompletion(SessionImpl.java:3212)
	at org.hibernate.internal.SessionImpl.beforeTransactionCompletion(SessionImpl.java:2380)
	at org.hibernate.engine.jdbc.internal.JdbcCoordinatorImpl.beforeTransactionCompletion(JdbcCoordinatorImpl.java:447)
	at org.hibernate.resource.transaction.backend.jdbc.internal.JdbcResourceLocalTransactionCoordinatorImpl.beforeCompletionCallback(JdbcResourceLocalTransactionCoordinatorImpl.java:183)
	at org.hibernate.resource.transaction.backend.jdbc.internal.JdbcResourceLocalTransactionCoordinatorImpl.access$300(JdbcResourceLocalTransactionCoordinatorImpl.java:40)
	at org.hibernate.resource.transaction.backend.jdbc.internal.JdbcResourceLocalTransactionCoordinatorImpl$TransactionDriverControlImpl.commit(JdbcResourceLocalTransactionCoordinatorImpl.java:281)
	at org.hibernate.engine.transaction.internal.TransactionImpl.commit(TransactionImpl.java:101)
	at io.onedev.server.persistence.DefaultTransactionManager$1.call(DefaultTransactionManager.java:73)
	at io.onedev.server.persistence.DefaultSessionManager.call(DefaultSessionManager.java:79)
	at io.onedev.server.persistence.DefaultTransactionManager.call(DefaultTransactionManager.java:60)
	at io.onedev.server.persistence.TransactionInterceptor.invoke(TransactionInterceptor.java:18)
	at io.onedev.server.notification.DefaultMailManager$4$1.onReceived(DefaultMailManager.java:730)
	at io.onedev.server.notification.DefaultMailManager$5.processMessages(DefaultMailManager.java:788)
	at io.onedev.server.notification.DefaultMailManager$5.run(DefaultMailManager.java:855)
	at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
	at java.util.concurrent.FutureTask.run(FutureTask.java:266)
	at io.onedev.server.security.SecurityUtils$1.run(SecurityUtils.java:352)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
	at java.lang.Thread.run(Thread.java:748)
Caused by: org.hibernate.exception.ConstraintViolationException: could not execute statement
	at org.hibernate.exception.internal.SQLExceptionTypeDelegate.convert(SQLExceptionTypeDelegate.java:59)
	at org.hibernate.exception.internal.StandardSQLExceptionConverter.convert(StandardSQLExceptionConverter.java:42)
	at org.hibernate.engine.jdbc.spi.SqlExceptionHelper.convert(SqlExceptionHelper.java:113)
	at org.hibernate.engine.jdbc.spi.SqlExceptionHelper.convert(SqlExceptionHelper.java:99)
	at org.hibernate.engine.jdbc.internal.ResultSetReturnImpl.executeUpdate(ResultSetReturnImpl.java:200)
	at org.hibernate.persister.entity.AbstractEntityPersister.insert(AbstractEntityPersister.java:3301)
	at org.hibernate.persister.entity.AbstractEntityPersister.insert(AbstractEntityPersister.java:3828)
	at org.hibernate.action.internal.EntityInsertAction.execute(EntityInsertAction.java:107)
	at org.hibernate.engine.spi.ActionQueue.executeActions(ActionQueue.java:604)
	at org.hibernate.engine.spi.ActionQueue.lambda$executeActions$1(ActionQueue.java:478)
	at java.util.LinkedHashMap.forEach(LinkedHashMap.java:684)
	at org.hibernate.engine.spi.ActionQueue.executeActions(ActionQueue.java:475)
	at org.hibernate.event.internal.AbstractFlushingEventListener.performExecutions(AbstractFlushingEventListener.java:348)
	at org.hibernate.event.internal.DefaultFlushEventListener.onFlush(DefaultFlushEventListener.java:40)
	at org.hibernate.event.service.internal.EventListenerGroupImpl.fireEventOnEachListener(EventListenerGroupImpl.java:102)
	at org.hibernate.internal.SessionImpl.doFlush(SessionImpl.java:1362)
	... 21 common frames omitted
Caused by: java.sql.SQLIntegrityConstraintViolationException: integrity constraint violation: unique constraint or index violation; UKA4H1UNN42YUVXDKXL1HKTEUUX table: O_ISSUEWATCH
	at org.hsqldb.jdbc.JDBCUtil.sqlException(Unknown Source)
	at org.hsqldb.jdbc.JDBCUtil.sqlException(Unknown Source)
	at org.hsqldb.jdbc.JDBCPreparedStatement.fetchResult(Unknown Source)
	at org.hsqldb.jdbc.JDBCPreparedStatement.executeUpdate(Unknown Source)
	at com.zaxxer.hikari.pool.ProxyPreparedStatement.executeUpdate(ProxyPreparedStatement.java:61)
	at com.zaxxer.hikari.pool.HikariProxyPreparedStatement.executeUpdate(HikariProxyPreparedStatement.java)
	at org.hibernate.engine.jdbc.internal.ResultSetReturnImpl.executeUpdate(ResultSetReturnImpl.java:197)
	... 32 common frames omitted
Caused by: org.hsqldb.HsqlException: integrity constraint violation: unique constraint or index violation; UKA4H1UNN42YUVXDKXL1HKTEUUX table: O_ISSUEWATCH
	at org.hsqldb.error.Error.error(Unknown Source)
	at org.hsqldb.Constraint.getException(Unknown Source)
	at org.hsqldb.index.IndexAVLMemory.insert(Unknown Source)
	at org.hsqldb.persist.RowStoreAVL.indexRow(Unknown Source)
	at org.hsqldb.TransactionManagerMVCC.addInsertAction(Unknown Source)
	at org.hsqldb.Session.addInsertAction(Unknown Source)
	at org.hsqldb.Table.insertSingleRow(Unknown Source)
	at org.hsqldb.StatementDML.insertSingleRow(Unknown Source)
	at org.hsqldb.StatementInsert.getResult(Unknown Source)
	at org.hsqldb.StatementDMQL.execute(Unknown Source)
	at org.hsqldb.Session.executeCompiledStatement(Unknown Source)
	at org.hsqldb.Session.execute(Unknown Source)
	... 37 common frames omitted

Thanks for reporting. Fixed in build #2572