Existing Mutual Fund Transactions Problem

I have an existing (for years) mutual fund that suddenly is not recognized. When I try to enter a reinvestment transaction and enter the security symbol, it shows up as new. If I look at holdings the security is there with the correct symbol. I can't seem to add any new transactions for that security. I tried validate and repair but it did not help. What can I do to add transactions for that security? TIA.