Banking verification code leaves busy signal and voicemail afterward

Suddenly I can’t log into online banking because the verification codes I keep trying to get won’t come though. My phone rings (wireless home phone hub), I answer and always get a busy signal. After this, I get a voicemail which is from the bank (the automated voice I’m supposed to be hearing telling me to press 1 so as to hear the code I’m looking for). After several attempts, this keeps happening. 

Should I be waiting for a network glitch to go away, or might there be some separate issue I need to address? I’ve never had this problem before. This phone hub is newer than my previous one (upgraded 3G to 4G LTE some weeks ago) and this is the first time I’m having to have a verification code sent through it. Yes, I have Call Control active but the phone number my financial institution uses is whitelisted and has been for a long time.