unityhub1.4 ask me to active license again and again, i noticed it delete the "C:\ProgramData\Unity\Unity_lic.ulf" every restart. the .ulf file is generated by activing unity2018. I filled the right serial number, it would tell me 'serial has reached the maximum number of activations', i removed the actived machine from account page, active would be successful. But! start unityhub next time, it ask me to active again!