[ride-the-lightning] Error changing block explorer URL

[jjmmbb]

Every time I have tried to replace mempool.space url to use local mempool that error is being displayed:

Update Node Settings Failed!
Error Code
400
Error Message
Http Failure Response For Http://umbrel.local:3001/rtl/api/conf/node: 400 Bad Request
API URL
./api/conf/node

Anyone know how to fix it?