Do what error08 says, I can only think of two reasons on why this is happening. First is because its buggy, Second would be because it is receiving a high traffic.
Here are the other block explorers that you want to try to determine what is really happening.
This one updates every two days from what I know so it might be useless if you had recent transactions but it displays all related addresses from an account so if you have unspent outputs from many addresses, it will be helpful. Here it is: https://www.walletexplorer.com
It says at the bottom: Updated to block 500259 (2017-12-20 10:57:09). All times are in UTC and taken from block time. So it means transactions over that time is not recorded in their database and if you had one, don't use it and refer only to the links quoted above^.
Thanks
Try to update (If any) or just reinstall the app but be sure that you have backed up your recovery phrase first.