To fix login to admin panel in WordPress

Now instead of logging in to the admin white page

The answer from tech support hosting:
The observed failure of the administration panel of Your website. The problem occurs because of the presence of the BOM signature in the files of the website. Many text editors for Windows add the bytes 0xEF, 0xBB, 0xBF at the beginning of any document that is saved with the UTF-8 encoding. This is the byte order mark of Unicode (eng. Byte Order Mark, BOM) or BOM-signature. By the presence of signatures of the program can automatically detect whether the file is encoded in UTF-8, but files with the same signature may not be processed by the web server.
Please follow the recoding php files via the console, SSH, or a special text editor such as Notepad . After that check the correct operation of the administration panel.