SecNotes not working properly on my Samsung Galaxy S21 phone

The app worked great for the 1st month, now in the app on my phone, the notes freeze, add multiple rows between words, and I lose saved notes etc. I paid for the premium SecNotes and loved it. Now I find it very frustrating and unreliable to use to save important notes and messages. Works great on my desktop, but that is not effective for on-the-go use. Please help!