Hi,
For 1 Issue - Open classic / Developer environment. Search for CurrReport.PREVIEW and comment that part of code.
In Sales Invoice/ cr. memo report you will find it in two dataitems Sales Invoice Header & CopyLoop.
Just comment this part and then check the report.
For 2 Issue - Check that the font you have provided in report layout is installed in your machine or not.
Let me know if any issues.