Can't create new pages - "Unable to communicate with server. Saving is not possible at the moment"

[Fabian Duft]

Hi,

I am currently facing a major problem in Confluence 6.15.9.
If I want to save new pages I get the following error message: "Unable to communicate with server. Saving is not possible at the moment" I already looked into the solutions described here: https://community.atlassian.com/t5/Confluence-questions/Getting-error-quot-Unable-to-communicate-with-server-Saving-is/qaq-p/27058
Neither collaborative editing, nor specific emojis are used.

The creation of Spaces as well as editing of already existing pages is still possible.

If I cancel the editing mode of a new page I get the following message:

com.atlassian.core.exception.InfrastructureException: org.springframework.dao.InvalidDataAccessResourceUsageException: could not extract ResultSet; SQL [n/a]; nested exception is org.hibernate.exception.SQLGrammarException: could not extract ResultSet
    at com.atlassian.confluence.core.persistence.hibernate.HibernateObjectDao.remove(HibernateObjectDao.java:263)

caused by: org.springframework.dao.InvalidDataAccessResourceUsageException: could not extract ResultSet; SQL [n/a]; nested exception is org.hibernate.exception.SQLGrammarException: could not extract ResultSet
    at org.springframework.orm.hibernate5.SessionFactoryUtils.convertHibernateAccessException(SessionFactoryUtils.java:224)

caused by: org.hibernate.exception.SQLGrammarException: could not extract ResultSet
    at org.hibernate.exception.internal.SQLStateConversionDelegate.convert(SQLStateConversionDelegate.java:106)

caused by: org.postgresql.util.PSQLException: ERROR: relation "extrnlnks" does not exist Position: 468
    at org.postgresql.core.v3.QueryExecutorImpl.receiveErrorResponse(QueryExecutorImpl.java:2476)

Can someone help me?

[repi]

@Fabian Duft 

I would simply restart the confluence.
First move the log files to only have log data for the restart.

[Fabian Duft]

@repi 
Thank you for your reply.
I forgot to mention that we already restarded Confluence, but this didn't solve the problem.

[repi]

Do you have a support capable confluence license?
If so, contact atlassian support.
There seems to be a problem with the Postgresql DB.

[Fabian Duft]

I have tried to contact an atlassian support with a ticket before, but I got no reply so far. That's why I opened the question in the Atlassian Community.
I also do think that this is as problem with the PostgreSQL DB but I don't know how to solve this.

[repi]

Don't you have a DB Admin who knows postgresql well?
Have there been any changes to the confluence or to the db server?

[Fabian Duft]

There have been no active changes from our side.