Unknown "Failed to log on "xxx" with username"".

help? is anyone had the same issue?

Update to version 15.4.4 and read the note in the changelog about OpenSubtitles.

Thanks it is fixed now

I also had this error updating to 15.4.4 fixed the error message but now the player cannot find any subtitles it simply reads "no subtitles found" tried with many different movies and tv series

Subtitle search in MPC-HC using OpenSubtitles currently requires a login. OpenSubtitles has implemented this restriction because their servers are being overloaded now that many people are staying at home. You can create a free account on the opensubtitles.org website. You can then use these login details here: MPC-HC options > Subtitles > Misc > right-click on OpenSubtitles > Setup

Admin wrote:Subtitle search in MPC-HC using OpenSubtitles currently requires a login. OpenSubtitles has implemented this restriction because their servers are being overloaded now that many people are staying at home. You can create a free account on the opensubtitles.org website. You can then use these login details here: MPC-HC options > Subtitles > Misc > right-click on OpenSubtitles > Setup

That worked like a charm! Thank you for your response.