I installed TVHeadend on OSMC and on the step of configuring the user and password I changed them but now when I try to login to the web-UI, Tvheadend doesn´t recognise the new password neither the older.
I’ve tried to reinstall TvHeadend but I have the same issue.
How can I change the password?
I recommend you don’t mess with the defaults until you have everything working. Then use the webui to change the password in Configuration->Users->Passwords and make the corresponding change in the TVH client. (If you must.)
Uninstall TVH, delete the configuration files with rm -r /home/osmc/.hts
then install again.