Probably a last resort option, but if you really want your homebrew now, numerous people have reported instant success with browserhax and the kexploit straight after updating to 5.5.1.
Some other options include resetting your browser's save data (this potentially moves some cache memory region or something, which aids browserhax somehow).
Some people also have success with certain websites, but not others (e.g. someone has 100% success with loadiine.ovh, but has 0% success with wiiubru.com). Try using other sites.
Another thing to try is self-hosting. Browserhax needs to be transferred to your console fast enough so that the entire ROP chain is loaded, as the Wii U tends to start reading the data before it is finished downloading.
Try some of these options, and if you still don't have success, then something is wrong (that people around here may or may not be able to help with).