I wrote in my question that I use hsqldb.
Yes, everything works on this site. That's why I asked.
There are no errors in the Tomcat log.
jforum.log I found only in the hsqldb directory. Is that him?
/*C17*/SET SCHEMA PUBLIC
INSERT INTO JFORUM_PRIVMSGS VALUES(1,2,'test private send',3,2,'2020-04-11 06:44:45.282000','0:0:0:0:0:0:0:1',1,0,1,1)
INSERT INTO JFORUM_PRIVMSGS_TEXT VALUES(1,'jforum-2.6.2')
INSERT INTO JFORUM_PRIVMSGS VALUES(2,1,'test private send',3,2,'2020-04-11 06:44:45.282000','0:0:0:0:0:0:0:1',1,0,1,1)
INSERT INTO JFORUM_PRIVMSGS_TEXT VALUES(2,'jforum-2.6.2')
COMMIT
DISCONNECT
/*C18*/SET SCHEMA PUBLIC
DISCONNECT
/*C19*/SET SCHEMA PUBLIC
DISCONNECT
/*C20*/SET SCHEMA PUBLIC
DISCONNECT