We would like to remind you that on weekends, only the crypto markets remain open.
Additionally, always check the rollover/session hours for a given instrument in the specifications, as well as your MT5 mailbox to determine if there might be a scheduled market closing.
Are you accessing different account types?
Regarding switching charts between different account types:
Different account types support symbols with different extensions. For example, on a RAW account: EURUSD.ecn, on an Unlimited account: EURUSD#.
Due to this, the chart may not open correctly after switching to a different account type. If the accounts are of the same type, the charts should open correctly.