@sasha Abdullin – This is the styles currently being rendered for Popup Theme #368.
Edit that theme and change its name to something in either in latin/english characters or numeric and save. The popup that opens on that button currently uses this broken theme.
/* Popup Theme 368: Тема по умолчанию */
.popmake-overlay.theme-368, .popmake-overlay.theme-%d1%82%d0%b5%d0%bc%d0%b0-%d0%bf%d0%be-%d1%83%d0%bc%d0%be%d0%bb%d1%87%d0%b0%d0%bd%d0%b8%d1%8e { background-color: rgba( 255, 255, 255, 1 ) }
.popmake.theme-368, .popmake.theme-%d1%82%d0%b5%d0%bc%d0%b0-%d0%bf%d0%be-%d1%83%d0%bc%d0%be%d0%bb%d1%87%d0%b0%d0%bd%d0%b8%d1%8e { padding: 18px; border-radius: 0px; border: 1px none #000000; box-shadow: 1px 1px 3px 0px rgba( 2, 2, 2, 0.23 ); background-color: rgba( 249, 249, 249, 1 ) }
.popmake.theme-368 .popmake-title, .popmake.theme-%d1%82%d0%b5%d0%bc%d0%b0-%d0%bf%d0%be-%d1%83%d0%bc%d0%be%d0%bb%d1%87%d0%b0%d0%bd%d0%b8%d1%8e .popmake-title { color: #000000; text-align: left; text-shadow: 0px 0px 0px rgba( 2, 2, 2, 0.23 ); font-family: inherit; font-size: 32px; line-height: 36px }
.popmake.theme-368 .popmake-content, .popmake.theme-%d1%82%d0%b5%d0%bc%d0%b0-%d0%bf%d0%be-%d1%83%d0%bc%d0%be%d0%bb%d1%87%d0%b0%d0%bd%d0%b8%d1%8e .popmake-content { color: #8c8c8c; font-family: inherit }
.popmake.theme-368 > .popmake-close, .popmake.theme-%d1%82%d0%b5%d0%bc%d0%b0-%d0%bf%d0%be-%d1%83%d0%bc%d0%be%d0%bb%d1%87%d0%b0%d0%bd%d0%b8%d1%8e > .popmake-close { height: 10px; width: 10px; left: auto; right: 0px; bottom: auto; top: 0px; padding: 8px; color: #ffffff; font-family: inherit; font-size: 12px; line-height: 14px; border: 1px none #ffffff; border-radius: 0px; box-shadow: 0px 0px 0px 0px rgba( 2, 2, 2, 0.23 ); text-shadow: 0px 0px 0px rgba( 0, 0, 0, 0.23 ); background-color: rgba( 0, 183, 205, 1 ) }
Alternatively you could edit your popup and change it to use the Style 1 theme on the right side when your in the popup editor.
Hope that helps.