Check out how to tune your heater in the wiki here:
https://duet3d.com/wiki/Tuning_the_heater_temperature_control
The error you have is based on the firmware believing you have a powerful heater that could reach the temperature indicated if left fully on. This might not be the case, see how you get on with the tuning.
For the second one check your tool change macros it may be you have a retract command in there that executed on tool change, but that retract won't work if the hotend is not hot enough. This is one of the reasons why I don't have retract commands in tool change macros. Instead I use the slicer tool change settings to deal with retraction.
