You may encounter email display problem in webmail account when your web browser stored too many temporary data (e.g. browsing history, cookies or cache, etc.). You may try login using another web browser or resetting your current browser to its default condition.
Resetting web browser may remove your browser and personal settings. Please refer to https://www.its.hku.hk/faq/personal/pc/general/delete-browsing-history to delete browser cache procedure