Sending email

Problem since mid-afternoon yesterday. I can receive email but can't send. This problem is with both comcast and gmail. The outlook 365 for MAC message is can't connect to server. For a short while about 12PM today, I was able to send using gmail and cleared my outbox by changing to gmail from comcast. But now gmail won't work again either. This is suspicious that BOTH servers aren't working at the same time? My husband using windows outlook 365 is not having problems. Is the problem related to MAC only?