Siemens MP277 10" troubles

Hello
Since a moment (6 months) I have some strange troubles with MP277 10" HMI
When we power ON (after somedays OFF) the machine; the HMI is unable to start and screen is sometime black; sometime it lit and after a moment it goes black.
I take it out of machine and open it: I spray the liquid electronic bomb-contact and put the card on the sun for drying.
Back on site and after some minutes all is OK and it runs fine.
What must be the cause of this?
NOTA:the HMI is for a sterilizer and the environment is a bit warm and humid
Hope to read you soon
Best regards

Moisture and electronics don't work well together. You probably need to either add a heater to the enclosure to keep it dry (if the ambient temperature is low enough). Or add an enclosure air conditioner to keep the temperature and humidity down.
Also make sure the enclosure is sealed well.

Thank you sir for your reply.
there's already a fan, but it's not working.I'll change it and see
Thanks for your post
Best regards