Hey,
with the following search (you probably have used something similar to find this thread):
https://central.owncloud.org/search?q=%22you%20took%20too%20long%20to%20login%22
i found a few other threads where others have reported some observations:
With the following two a reinstall of the packages “worked”: You took too long to login, please try again now, Stuck on WEB UI Login screen
Here a “http” vs. “https” have been observed which makes a difference: Login fails “You took too long to login, please try again now”
With this an update of PHP worked: Cannot login to Owncloud X after a fresh install
This seems to be unanswered but i just want to add a reference to it anyway: Problem with login