Seems pretty clear to me. Your quarantine has run out of space. Look at the Store and Forward system’s status page and look at what’s in quarantine.
I turned off the “tags.execution.actors.history” logger and now that message is gone/hidden.
I now see that there is another error when looking at the Store and Forward page:
java.lang.AbstractMethodError:
Receiver class com.mysql.jdbc.Connection does not define or inherit an implementation of the resolved method abstract getSchema()Ljava/lang/String; of interface java.sql.Connection
That would be fine with a new Ignition system, but if your gateway backup is old, it’s possible your embedded JDBC driver is too far out of date - it’s still worth attempting the update.
Following the guide did seem to help some but I don’t see how to Reinitialize the database connection and store and forward page did show something but now is stuck loading.
Just edit the DB connection that’s stuck loading, then save changes (even though you didn’t make any). That should restart the connection if there’s some issue.
If that’s still not working, then I would encourage you to contact support - this might be past what can really be troubleshooted via the forums.