your problem is simple you are using the rate priority too high for the amount you want to send just lower the priority or decrease the amount to be sent both have to match the amount you want to send
I don't think this is the problem.
With 3 sat/byte this dude will need extra 0.01566 mBTC with today's transaction date. It is tiny amount with what he his transacting. The wallet has balance of 0.012 BTC while all he is needing in the form of fees is 0.000011 BTC to proceed with it.
We can notice he is transferring 0.011 BTC, thus he is still left with 0.001 BTC in his wallet and enough to cut the fees.
3 sat/byte would make up 522 bytes for 0.011 BTC weightage. Based on this, he is all good with the fees and all.
The problem is something different for sure.