Cannot delete auxiliary email adress

Hi Mozilla community! I am having issues deleting old, obsolete auxiliary email address. It prompts me to confirm this with the verification code sent to my email address. However, the prompt does not accept the verification code and times out due to too many attempt after i tried inputting and confirming the code 5-6 times. Before the time out the prompt window does not show any sign of reaction to me inputting and confirming the code. Does any one faced issue like this before? Do you know workarounds? Would there be a way to add second auxiliary email address or change this one instead of deleting? Thanks in advance for all suggestions! Best, Rafal