We've set up a Zabbix Proxy but can't get it to execute web monitoring scenarios.  We get the error "failed to update local proxy configuration copy: column "items.params" cannot be null".  We've tried using PostgreSQL, MySQL, and SQLite as our proxy DB.  We've tried lifting the non-null constraint from the params column of the items table.  We've configured it as both an active and passive proxy.  We've tried versions 3.4.2, 3.4.8,  and 3.4.10.  (The server is running 3.4.8.)  We still get the same error message.

zabbix-get-3.4.10-1.el7.x86_64
zabbix-proxy-pgsql-3.4.10-1.el7.x86_64
zabbix-release-3.4-2.el7.noarch

Steps to reproduce:

1. Create proxy
2. Set up web scenario
3. Assign host to proxy
4. Check proxy log when no data collected

Result:

From /var/log/zabbix/zabbix_proxy.log:

12410:20180615:190847.385 query [txnlev:1] [select itemid,type,snmp_community,snmp_oid,hostid,key_,delay,status,value_type,trapper_hosts,snmpv3_securityname,snmpv3_securitylevel,snmpv3_authpassphrase,snmpv3_privpassphrase,lastlogsize,logtimefmt,params,ipmi_sensor,authtype,username,password,publickey,privatekey,mtime,flags,interfaceid,port,snmpv3_authprotocol,snmpv3_privprotocol,snmpv3_contextname,jmx_endpoint from items]
12410:20180615:190847.386 End of process_proxyconfig_table():FAIL
12410:20180615:190847.386 query [txnlev:1] [rollback;]
12410:20180615:190847.386 failed to update local proxy configuration copy: column "items.params" cannot be null
12410:20180615:190847.386 End of process_proxyconfig()
12410:20180615:190847.386 End of process_configuration_sync()
12410:20180615:190847.386 __zbx_zbx_setproctitle() title:'configuration syncer [synced config 4544 bytes in 0.037040 sec, idle 3600 sec]'
12421:20180615:190848.334 __zbx_zbx_setproctitle() title:'self-monitoring [processing data]'

Versions:

zabbix-get-3.4.10-1.el7.x86_64
zabbix-proxy-pgsql-3.4.10-1.el7.x86_64
zabbix-release-3.4-2.el7.noarch