Monday is deadline day for the filing of Swedish tax returns and many elect to use the option to declare online. The agency website has however once again proved ill-equipped to deal with the large number of people out in the eleventh hour.
"There are many who have waited to declare and it means more pressure on our electronic services. If you are logged out, we hope you exercise patience and have another try," a statement on the agency's website on Monday read.
The agency expects that a record number of Swedes will elect to use the online option to file their taxes in 2011.
With the deadline set to fall at midnight on Monday, it is forecast that 4.6-4.7 million people (of a total adult population of around 7.5 million) will use the internet to register their taxes.
Last year some 4.35 million people filed their taxes electronically.
A new innovation this year has been the option to declare using an application for the iPhone and Android.
The Tax Agency has increased its online capacity after problems in 2010, but remains uncertain that the system will cope and has issued several statements urging Swedes to avoid the last minute rush.