The first console message is a consequence (not a cause) of the tiles not loading (auto-ranging can’t work until there is data rendered to auto-range). The second console message is not from/related to Bokeh (messages about missing source map files are harmless in any case).
The best place to looks for clues is probably in the browser’s network tab, which will show all the individual network requests for the tiles and also any related status codes, errors, etc. The way browser dev tools are opened differs by browser, so you will have to google search how to access them for whatever specific browser you are using.