If error code is oo7, then there is some problem with firewall or anti-virus application. If error code is 008, it means attachment size is greater than 20MB. If error code is 009, Gmail will load itself in upper left corner of screen. If error code is 102, Unknown error. Try basic HTML version. If error code is 500, Problem with network connection or browser extension. – Receiving, deleting, or downloading large amounts of mail via POP or IMAP in a short period of time. – Sending a large number of undeliverable messages. – Leaving multiple instances of Gmail open at different places. Don’t panic! Gmail will be accessible within 24 hours. – Mobile browser must to be XHTML compliant. Test computability by searching anything in www.google.com/xhtml. – Mobile browser must have cookies enabled. – Phone network must allow secure SSL traffic. Probably due to non-usage of Gmail for continuous 9 months or due to abnormal/suspicious usage. Gmail has the following limitations on its users : – You can only send 500 mails in a day. (Thats 500 times hitting the send button) – There could be maximum 500 unique recipients for a single mail. – Maximum limit of sent mails is 2000 in a day (for example, sending one message to a group of 500 people four times)