This is an old issue or bug of copay wallet but i think its a server issue did you tried to update the copay first maybe the old copay wallet is no longer support and disconnected to bitcore..
Try update it..
Hope that you are always backup your wallet before you are depositing in any wallet because if the wallet crash you can recover your wallet in other supported wallet..
I suggest you to wait in 24 hours if the update not work then once its working again better to move to other wallet instead i suggest you to use the latest electrum wallet to hold your bitcoin ..
Edit: Just add this link
https://github.com/bitpay/copay/issues/5197and looks like other user's didn't solve their issue..
