Try putting your homepage URL into our robots simulator to see what links are found on your page.
https://www.xml-sitemaps.com/se-bot-simulator.htmlBear in mind that whatever the results are on this is likely to be the same for search engine robots. If you have links that aren't picked up by this then the search engine robots are not going to find them either.
Possible causes are links embeded in Flash or Javascript menus.
The following is taken from Google's Webmaster Guidelines
"Use a text browser such as Lynx to examine your site, because most search engine spiders see your site much as Lynx would. If fancy features such as JavaScript, cookies, session IDs, frames, DHTML, or Flash keep you from seeing all of your site in a text browser, then search engine spiders may have trouble crawling your site."