I once had to deal with a major retail park where all the stores were reporting a similar problem at the same time. Their card transactions were not going through . I got called out at silly o'clock to go there and have a look as the techy boys off site could not see the problem....
it was a wireless link to a 3G mast that someone built a building near and blocked the signal...
Solution was a Fibre Cable run of about 3 miles... So we dug two different routes in case someone else descided to put a digger through one...and yes some one did 😊