Trouble with pex enabled in transmission

So I have a problem with transmission after an upgrade OMV2 to OMV3.
I think it is my former config in OMV 2 wich is not recognied in OMV 3

Something with pex and rpc I think.
I try to disable and enable pex and/or RPC settings trough the webgui but I have allways the same message.

The property 'pexenabled' does not exist in the model 'conf.service.transmissionbt'.

He are the details

exception 'OMV\AssertException' with message 'The property 'pexenabled' does not exist in the model 'conf.service.transmissionbt'.' in /usr/share/php/openmediavault/config/configobject.inc:71Stack trace:#0 /usr/share/php/openmediavault/config/configobject.inc(186): OMV\Config\ConfigObject->assertExists('pexenabled')#1 /usr/share/php/openmediavault/config/configobject.inc(271): OMV\Config\ConfigObject->set('pexenabled', '1', false)#2 /usr/share/php/openmediavault/config/configobject.inc(233): OMV\Config\ConfigObject->setFlatAssoc(Array, false, false)#3 /usr/share/php/openmediavault/config/database.inc(90): OMV\Config\ConfigObject->setAssoc(Array, false)#4 /usr/share/openmediavault/engined/module/transmissionbt.inc(129): OMV\Config\Database->get('conf.service.tr...')#5 /usr/share/openmediavault/engined/rpc/config.inc(194): OMV\Engined\Module\TransmissionBt->startService()#6 [internal function]: OMVRpcServiceConfig->applyChanges(Array, Array)#7 /usr/share/php/openmediavault/rpc/serviceabstract.inc(124): call_user_func_array(Array, Array)#8 /usr/share/php/openmediavault/rpc/serviceabstract.inc(150): OMV\Rpc\ServiceAbstract->callMethod('applyChanges', Array, Array)#9 /usr/share/php/openmediavault/rpc/serviceabstract.inc(528): OMV\Rpc\ServiceAbstract->OMV\Rpc\{closure}('/tmp/bgstatusfF...', '/tmp/bgoutpute6...')#10 /usr/share/php/openmediavault/rpc/serviceabstract.inc(151): OMV\Rpc\ServiceAbstract->execBgProc(Object(Closure))#11 /usr/share/openmediavault/engined/rpc/config.inc(213): OMV\Rpc\ServiceAbstract->callMethodBg('applyChanges', Array, Array)#12 [internal function]: OMVRpcServiceConfig->applyChangesBg(Array, Array)#13 /usr/share/php/openmediavault/rpc/serviceabstract.inc(124): call_user_func_array(Array, Array)#14 /usr/share/php/openmediavault/rpc/rpc.inc(86): OMV\Rpc\ServiceAbstract->callMethod('applyChangesBg', Array, Array)#15 /usr/sbin/omv-engined(536): OMV\Rpc\Rpc::call('Config', 'applyChangesBg', Array, Array, 1)#16 {main}

Do i have to uninstall and reinstall transmision trough the webgui or can i fix it on SSH ?

Allready done. And it does not change anything.

I will try this evening but I prefer not to use chrome.
I rather use firefox. Why did i have to use the browser un private mode ?

I can also clean the browser cache.
Thank you for your help.

I just reinstall

apt-get purge openmediavault-transmissionbt

Then i open firefox clear the cache and reinstall transmission trough the webgui.
Putting the same settings as in OMV 2 for pex and webrpc and it works
Thanks subzero79