Warning to all.
I found that Blockchain.info is setting the fees too low since some days! I ran into that problem 2 times now and never before all the years.
You have to check the fee manually before sending if you use a blockchain.info wallet or it will set something like 35sat/B, which is way too low for the current backlog: https://bitcoinfees.21.co
Solution: Go to VIAbtc Transaction Accelerator (https://www.viabtc.com/tools/txaccelerator/) and try it around the full hour change, then the limit will be reset(only 100 per hour allowed). If its accepted, the TX is in the next block they find. It's free and all you need to do is put in the TX ID.
It worked for me with 2 TXs that were stuck for 3 days.
good luck to all of you
I got this error: Submissions are beyond limit. Please try later.
I tried it for last several hours.