Snow Blowers

I have a ST 230 E snow blower. The auger lever gets stuck in in “ENGAGE” position. The only way to release it is by depressing the little spring loaded switch beside the lever. Any ideas on what is wrong would be appreciated as this is quite dangerous. I have attached a picture and it is the black plastic release with the channel in the middle that needs to be depressed to disengage the auger and release the lever

Thanks
Tony