Some Players have reported being able to join a Corporation by closing the game completely and turning off their device for a few minutes before trying again, but many have not been successful in doing so.
If the above workaround did not work for you, we unfortunately cannot offer you an alternative aside from waiting for a future update in which the error may be corrected.
Rest assured that the Corporation feature is an entirely optional part of the game and Players are not hindered in their progression by opting out. Many Players reach the highest Level available without ever being part of a Corporation.
We thank you for your understanding and patience while this issue remains active and apologize for the inconvenience this may bring your gaming experience.