We are sorry, deposit of XTZ is temporarily paused due to node upgrade. Please try again later.
Does it seem serious to you that I have to do this to be heard?
I neve use OKEx and don't have plans of using them but i cannot find any bad reputation on them so meaning so far they are cool.
Maybe they are having some Upgrade and it's just happen that the timing is from your depositing time, try to extend your patience and if the issue persist for long then better to file a formal scam accusation against them in right section.