Unable to join/post in groups

So my problem is, i have tries this with a few accounts. ALL phone verified and ALL over 1-2 months old.

I first access the account with a brand new proxy, new phone number ect. I do some "REAL" activity on the account, liking pages, posting statuses, liking books ect. Then i join about 12 groups and i get an error message

Action Blocked
You have been temporarily blocked from performing this action.
If you think you're seeing this by mistake, please let us know.

This goes for posting in those groups aswell.

Any facebook experts out there can point out my problem?

Thanks in advance

Edit: My goal for these accounts is to add 5,000 friends

Fb has limited the number of groups you can join a day in safety
I have found if you keep to 3 or less your pretty safe for now

Thanks, i'll give that a try

Perhaps, you have been joining groups consecutively within a day or two. This is the same issue when you like a great number of posts in a short time.

Could be the cookie in your computer.