my serial port doesn't work!
It says that it's unavaiable
how can I solve the problem?
What is the "it" that says that the other "it" is unavailable?
Steve
Which operating system?
Which version of the IDE?
Which board? Genuine Arduino or clone?
Bad or charge only USB cable?
Did you select the correct serial port?
What does Windows device manager (or Linux/Mac equivalents) say when you connect the board?
I agree with the previous answers. One more thing to consider is your USB port. Some USB ports on my laptop for example seem to not have COM compatibility. Maybe even try another computer or try your phone with an OTG cable and a serial monitor app