As a seller, selling or Amazon brings many options to fulfill orders. Once such option is easy ship prime or seller fulfilled prime. This option helps to make your listings prime while sending them through your premises instead of FBA. It is somewhat similar to Seller Flex.
In easy ship prime I faced issues like listing is not getting activated for prime. It is not showing prime label. After some mails with support team they repeatedly asked to check if account is prime enabled, if seller as a customer has prime membership (to check through prime account) and other things. These solutions didn’t prove to be useful.
Another action item (later on they told) was to check if item is having maximum package dimension as 50x35x30 cm. Item detail was missing packaging details. After updating package dimension of item within this range item got into prime (changes were done for only those items which were within this range).
It was success.