Maybe your resource credit is very low. The new upgrade steemit just did makes it difficult for accounts with low steem power to carry out activities on the platform. When you are low on RC, it becomes difficult to use the platform unless you have some steem to power up or you invest money in steem that you can use to power up.
This is the new situation of things in steemit now. They said that such change was done to reduce spam and make the plaform better for everyone. But they are preventing some genuine accounts from being able to use the platform. Just wait for your RC to recharge.