@Scottydog144 @Achim @jz831 - a Bitcoin Node app update was just released that should fix this issue for you (more info below). Can you please update your Bitcoin Node app and then restart Jam (right click on Jam from homescreen and select “restart”). Let me know if this fixes things for you.
Bitcoin Core v26.0 deprecated the RPC command for a certain type of wallet that JoinMarket uses. The newest Bitcoinn Node app update on Umbrel includes a fix to allow these wallets to be generated while the Jam devs work on supporting a new wallet type.